1645020840

# Introduction to Hypothesis Testing (Null and Alternative Hypotheses)

This statistics video tutorial provides a basic introduction into hypothesis testing.  It provides examples and practice problems that explains how to state the null and alternative hypotheses.

1593333600

## Introduction to Hypothesis Test (Part One)

Hypothesis test is one of the most important domain in statistics, and in industry, ‘AB Test’ utilizes this idea as well. However, most of

#ab-testing #statistics #hypothesis-testing #hypothesis #introduction #testing

1644415980

## SheetJS Community Edition - Spreadsheet Data Toolkit

SheetJS

The SheetJS Community Edition offers battle-tested open-source solutions for extracting useful data from almost any complex spreadsheet and generating new spreadsheets that will work with legacy and modern software alike.

SheetJS Pro offers solutions beyond data processing: Edit complex templates with ease; let out your inner Picasso with styling; make custom sheets with images/graphs/PivotTables; evaluate formula expressions and port calculations to web apps; automate common spreadsheet tasks, and much more!

Browser Test and Support Matrix

Supported File Formats

Diagram Legend (click to show)

## Getting Started

### Installation

The complete browser standalone build is saved to `dist/xlsx.full.min.js` and can be directly added to a page with a `script` tag:

``````<script lang="javascript" src="dist/xlsx.full.min.js"></script>
``````

CDN Availability (click to show)

For example, `unpkg` makes the latest version available at:

``````<script src="https://unpkg.com/xlsx/dist/xlsx.full.min.js"></script>
``````

Browser builds (click to show)

The complete single-file version is generated at `dist/xlsx.full.min.js`

A slimmer build is generated at `dist/xlsx.mini.min.js`. Compared to full build:

• codepage library skipped (no support for XLS encodings)
• XLSX compression option not currently available
• no support for XLSB / XLS / Lotus 1-2-3 / SpreadsheetML 2003
• node stream utils removed

Webpack and Browserify builds include optional modules by default. Webpack can be configured to remove support with `resolve.alias`:

``````  /* uncomment the lines below to remove support */
resolve: {
alias: { "./dist/cpexcel.js": "" } // <-- omit international support
}
``````

With npm:

``````\$ npm install xlsx
``````

With bower:

``````\$ bower install js-xlsx
``````

`dist/xlsx.extendscript.js` is an ExtendScript build for Photoshop and InDesign that is included in the `npm` package. It can be directly referenced with a `#include` directive:

``````#include "xlsx.extendscript.js"
``````

Internet Explorer and ECMAScript 3 Compatibility (click to show)

For broad compatibility with JavaScript engines, the library is written using ECMAScript 3 language dialect as well as some ES5 features like `Array#forEach`. Older browsers require shims to provide missing functions.

To use the shim, add the shim before the script tag that loads `xlsx.js`:

``````<!-- add the shim first -->
<script type="text/javascript" src="shim.min.js"></script>
<!-- after the shim is referenced, add the library -->
<script type="text/javascript" src="xlsx.full.min.js"></script>
``````

The script also includes `IE_LoadFile` and `IE_SaveFile` for loading and saving files in Internet Explorer versions 6-9. The `xlsx.extendscript.js` script bundles the shim in a format suitable for Photoshop and other Adobe products.

### Usage

Most scenarios involving spreadsheets and data can be broken into 5 parts:

Acquire Data: Data may be stored anywhere: local or remote files, databases, HTML TABLE, or even generated programmatically in the web browser.

Extract Data: For spreadsheet files, this involves parsing raw bytes to read the cell data. For general JS data, this involves reshaping the data.

Process Data: From generating summary statistics to cleaning data records, this step is the heart of the problem.

Package Data: This can involve making a new spreadsheet or serializing with `JSON.stringify` or writing XML or simply flattening data for UI tools.

Release Data: Spreadsheet files can be uploaded to a server or written locally. Data can be presented to users in an HTML TABLE or data grid.

A common problem involves generating a valid spreadsheet export from data stored in an HTML table. In this example, an HTML TABLE on the page will be scraped, a row will be added to the bottom with the date of the report, and a new file will be generated and downloaded locally. `XLSX.writeFile` takes care of packaging the data and attempting a local download:

``````// Acquire Data (reference to the HTML table)
var table_elt = document.getElementById("my-table-id");

// Extract Data (create a workbook object from the table)
var workbook = XLSX.utils.table_to_book(table_elt);

// Process Data (add a new row)
var ws = workbook.Sheets["Sheet1"];
XLSX.utils.sheet_add_aoa(ws, [["Created "+new Date().toISOString()]], {origin:-1});

// Package and Release Data (`writeFile` tries to write and save an XLSB file)
XLSX.writeFile(workbook, "Report.xlsb");
``````

This library tries to simplify steps 2 and 4 with functions to extract useful data from spreadsheet files (`read` / `readFile`) and generate new spreadsheet files from data (`write` / `writeFile`). Additional utility functions like `table_to_book` work with other common data sources like HTML tables.

This documentation and various demo projects cover a number of common scenarios and approaches for steps 1 and 5.

Utility functions help with step 3.

### The Zen of SheetJS

Data processing should fit in any workflow

The library does not impose a separate lifecycle. It fits nicely in websites and apps built using any framework. The plain JS data objects play nice with Web Workers and future APIs.

"Acquiring and Extracting Data" describes solutions for common data import scenarios.

"Writing Workbooks" describes solutions for common data export scenarios involving actual spreadsheet files.

"Utility Functions" details utility functions for translating JSON Arrays and other common JS structures into worksheet objects.

JavaScript is a powerful language for data processing

The "Common Spreadsheet Format" is a simple object representation of the core concepts of a workbook. The various functions in the library provide low-level tools for working with the object.

For friendly JS processing, there are utility functions for converting parts of a worksheet to/from an Array of Arrays. The following example combines powerful JS Array methods with a network request library to download data, select the information we want and create a workbook file:

Get Data from a JSON Endpoint and Generate a Workbook (click to show)

The goal is to generate a XLSB workbook of US President names and birthdays.

Acquire Data

Raw Data

https://theunitedstates.io/congress-legislators/executive.json has the desired data. For example, John Adams:

``````{
"id": { /* (data omitted) */ },
"name": {
"first": "John",          // <-- first name
"last": "Adams"           // <-- last name
},
"bio": {
"birthday": "1735-10-19", // <-- birthday
"gender": "M"
},
"terms": [
{ "type": "viceprez", /* (other fields omitted) */ },
{ "type": "viceprez", /* (other fields omitted) */ },
{ "type": "prez", /* (other fields omitted) */ } // <-- look for "prez"
]
}
``````

Filtering for Presidents

The dataset includes Aaron Burr, a Vice President who was never President!

`Array#filter` creates a new array with the desired rows. A President served at least one term with `type` set to `"prez"`. To test if a particular row has at least one `"prez"` term, `Array#some` is another native JS function. The complete filter would be:

``````const prez = raw_data.filter(row => row.terms.some(term => term.type === "prez"));
``````

Lining up the data

For this example, the name will be the first name combined with the last name (`row.name.first + " " + row.name.last`) and the birthday will be the subfield `row.bio.birthday`. Using `Array#map`, the dataset can be massaged in one call:

``````const rows = prez.map(row => ({
name: row.name.first + " " + row.name.last,
birthday: row.bio.birthday
}));
``````

The result is an array of "simple" objects with no nesting:

``````[
{ name: "George Washington", birthday: "1732-02-22" },
{ name: "John Adams", birthday: "1735-10-19" },
// ... one row per President
]
``````

Extract Data

With the cleaned dataset, `XLSX.utils.json_to_sheet` generates a worksheet:

``````const worksheet = XLSX.utils.json_to_sheet(rows);
``````

`XLSX.utils.book_new` creates a new workbook and `XLSX.utils.book_append_sheet` appends a worksheet to the workbook. The new worksheet will be called "Dates":

``````const workbook = XLSX.utils.book_new();
XLSX.utils.book_append_sheet(workbook, worksheet, "Dates");
``````

Process Data

By default, `json_to_sheet` creates a worksheet with a header row. In this case, the headers come from the JS object keys: "name" and "birthday".

The headers are in cells A1 and B1. `XLSX.utils.sheet_add_aoa` can write text values to the existing worksheet starting at cell A1:

``````XLSX.utils.sheet_add_aoa(worksheet, [["Name", "Birthday"]], { origin: "A1" });
``````

Fixing Column Widths

Some of the names are longer than the default column width. Column widths are set by setting the `"!cols"` worksheet property.

The following line sets the width of column A to approximately 10 characters:

``````worksheet["!cols"] = [ { wch: 10 } ]; // set column A width to 10 characters
``````

One `Array#reduce` call over `rows` can calculate the maximum width:

``````const max_width = rows.reduce((w, r) => Math.max(w, r.name.length), 10);
worksheet["!cols"] = [ { wch: max_width } ];
``````

Note: If the starting point was a file or HTML table, `XLSX.utils.sheet_to_json` will generate an array of JS objects.

Package and Release Data

`XLSX.writeFile` creates a spreadsheet file and tries to write it to the system. In the browser, it will try to prompt the user to download the file. In NodeJS, it will write to the local directory.

``````XLSX.writeFile(workbook, "Presidents.xlsx");
``````

Complete Example

``````// Uncomment the next line for use in NodeJS:
// const XLSX = require("xlsx"), axios = require("axios");

(async() => {
/* fetch JSON data and parse */
const url = "https://theunitedstates.io/congress-legislators/executive.json";
const raw_data = (await axios(url, {responseType: "json"})).data;

/* filter for the Presidents */
const prez = raw_data.filter(row => row.terms.some(term => term.type === "prez"));

/* flatten objects */
const rows = prez.map(row => ({
name: row.name.first + " " + row.name.last,
birthday: row.bio.birthday
}));

/* generate worksheet and workbook */
const worksheet = XLSX.utils.json_to_sheet(rows);
const workbook = XLSX.utils.book_new();
XLSX.utils.book_append_sheet(workbook, worksheet, "Dates");

/* fix headers */
XLSX.utils.sheet_add_aoa(worksheet, [["Name", "Birthday"]], { origin: "A1" });

/* calculate column width */
const max_width = rows.reduce((w, r) => Math.max(w, r.name.length), 10);
worksheet["!cols"] = [ { wch: max_width } ];

/* create an XLSX file and try to save to Presidents.xlsx */
XLSX.writeFile(workbook, "Presidents.xlsx");
})();
``````

For use in the web browser, assuming the snippet is saved to `snippet.js`, script tags should be used to include the `axios` and `xlsx` standalone builds:

``````<script src="https://unpkg.com/xlsx/dist/xlsx.full.min.js"></script>
<script src="https://unpkg.com/axios/dist/axios.min.js"></script>
<script src="snippet.js"></script>
``````

File formats are implementation details

The parser covers a wide gamut of common spreadsheet file formats to ensure that "HTML-saved-as-XLS" files work as well as actual XLS or XLSX files.

The writer supports a number of common output formats for broad compatibility with the data ecosystem.

To the greatest extent possible, data processing code should not have to worry about the specific file formats involved.

### JS Ecosystem Demos

The `demos` directory includes sample projects for:

Frameworks and APIs

Bundlers and Tooling

Platforms and Integrations

Other examples are included in the showcase.

## Acquiring and Extracting Data

### Parsing Workbooks

#### API

Extract data from spreadsheet bytes

``````var workbook = XLSX.read(data, opts);
``````

The `read` method can extract data from spreadsheet bytes stored in a JS string, "binary string", NodeJS buffer or typed array (`Uint8Array` or `ArrayBuffer`).

Read spreadsheet bytes from a local file and extract data

``````var workbook = XLSX.readFile(filename, opts);
``````

The `readFile` method attempts to read a spreadsheet file at the supplied path. Browsers generally do not allow reading files in this way (it is deemed a security risk), and attempts to read files in this way will throw an error.

The second `opts` argument is optional. "Parsing Options" covers the supported properties and behaviors.

#### Examples

Here are a few common scenarios (click on each subtitle to see the code):

Local file in a NodeJS server (click to show)

`readFile` uses `fs.readFileSync` under the hood:

``````var XLSX = require("xlsx");

var workbook = XLSX.readFile("test.xlsx");
``````

For Node ESM, the `readFile` helper is not enabled. Instead, `fs.readFileSync` should be used to read the file data as a `Buffer` for use with `XLSX.read`:

``````import { readFileSync } from "fs";
import { read } from "xlsx/xlsx.mjs";

const buf = readFileSync("test.xlsx");
/* buf is a Buffer */
const workbook = read(buf);
``````

User-submitted file in a web page ("Drag-and-Drop") (click to show)

For modern websites targeting Chrome 76+, `File#arrayBuffer` is recommended:

``````// XLSX is a global from the standalone script

async function handleDropAsync(e) {
e.stopPropagation(); e.preventDefault();
const f = e.dataTransfer.files[0];
/* f is a File */
const data = await f.arrayBuffer();
/* data is an ArrayBuffer */
const workbook = XLSX.read(data);

/* DO SOMETHING WITH workbook HERE */
}
``````

For maximal compatibility, the `FileReader` API should be used:

``````function handleDrop(e) {
e.stopPropagation(); e.preventDefault();
var f = e.dataTransfer.files[0];
/* f is a File */
var data = e.target.result;
/* reader.readAsArrayBuffer(file) -> data will be an ArrayBuffer */
var workbook = XLSX.read(data);

/* DO SOMETHING WITH workbook HERE */
};
}
``````

https://oss.sheetjs.com/sheetjs/ demonstrates the FileReader technique.

User-submitted file with an HTML INPUT element (click to show)

Starting with an HTML INPUT element with `type="file"`:

``````<input type="file" id="input_dom_element">
``````

For modern websites targeting Chrome 76+, `Blob#arrayBuffer` is recommended:

``````// XLSX is a global from the standalone script

async function handleFileAsync(e) {
const file = e.target.files[0];
const data = await file.arrayBuffer();
/* data is an ArrayBuffer */
const workbook = XLSX.read(data);

/* DO SOMETHING WITH workbook HERE */
}
``````

For broader support (including IE10+), the `FileReader` approach is recommended:

``````function handleFile(e) {
var file = e.target.files[0];
var data = e.target.result;
/* reader.readAsArrayBuffer(file) -> data will be an ArrayBuffer */
var workbook = XLSX.read(e.target.result);

/* DO SOMETHING WITH workbook HERE */
};
}
``````

The `oldie` demo shows an IE-compatible fallback scenario.

Fetching a file in the web browser ("Ajax") (click to show)

For modern websites targeting Chrome 42+, `fetch` is recommended:

``````// XLSX is a global from the standalone script

(async() => {
const url = "http://oss.sheetjs.com/test_files/formula_stress_test.xlsx";
const data = await (await fetch(url)).arrayBuffer();
/* data is an ArrayBuffer */
const workbook = XLSX.read(data);

/* DO SOMETHING WITH workbook HERE */
})();
``````

For broader support, the `XMLHttpRequest` approach is recommended:

``````var url = "http://oss.sheetjs.com/test_files/formula_stress_test.xlsx";

/* set up async GET request */
var req = new XMLHttpRequest();
req.open("GET", url, true);
req.responseType = "arraybuffer";

req.onload = function(e) {
var workbook = XLSX.read(req.response);

/* DO SOMETHING WITH workbook HERE */
};

req.send();
``````

The `xhr` demo includes a longer discussion and more examples.

http://oss.sheetjs.com/sheetjs/ajax.html shows fallback approaches for IE6+.

Local file in a PhotoShop or InDesign plugin (click to show)

`readFile` wraps the `File` logic in Photoshop and other ExtendScript targets. The specified path should be an absolute path:

``````#include "xlsx.extendscript.js"

/* Read test.xlsx from the Documents folder */
var workbook = XLSX.readFile(Folder.myDocuments + "/test.xlsx");
``````

The `extendscript` demo includes a more complex example.

Local file in an Electron app (click to show)

`readFile` can be used in the renderer process:

``````/* From the renderer process */
var XLSX = require("xlsx");

var workbook = XLSX.readFile(path);
``````

Electron APIs have changed over time. The `electron` demo shows a complete example and details the required version-specific settings.

Local file in a mobile app with React Native (click to show)

The `react` demo includes a sample React Native app.

Since React Native does not provide a way to read files from the filesystem, a third-party library must be used. The following libraries have been tested:

The `base64` encoding returns strings compatible with the `base64` type:

``````import XLSX from "xlsx";
import { FileSystem } from "react-native-file-access";

const b64 = await FileSystem.readFile(path, "base64");
/* b64 is a base64 string */
const workbook = XLSX.read(b64, {type: "base64"});
``````

The `ascii` encoding returns binary strings compatible with the `binary` type:

``````import XLSX from "xlsx";
import { readFile } from "react-native-fs";

const bstr = await readFile(path, "ascii");
/* bstr is a binary string */
const workbook = XLSX.read(bstr, {type: "binary"});
``````

NodeJS Server File Uploads (click to show)

`read` can accept a NodeJS buffer. `readFile` can read files generated by a HTTP POST request body parser like `formidable`:

``````const XLSX = require("xlsx");
const http = require("http");
const formidable = require("formidable");

const server = http.createServer((req, res) => {
const form = new formidable.IncomingForm();
form.parse(req, (err, fields, files) => {
/* grab the first file */
const f = Object.entries(files)[0][1];
const path = f.filepath;
const workbook = XLSX.readFile(path);

/* DO SOMETHING WITH workbook HERE */
});
}).listen(process.env.PORT || 7262);
``````

The `server` demo has more advanced examples.

Download files in a NodeJS process (click to show)

Node 17.5 and 18.0 have native support for fetch:

``````const XLSX = require("xlsx");

const data = await (await fetch(url)).arrayBuffer();
/* data is an ArrayBuffer */
const workbook = XLSX.read(data);
``````

For broader compatibility, third-party modules are recommended.

`request` requires a `null` encoding to yield Buffers:

``````var XLSX = require("xlsx");
var request = require("request");

request({url: url, encoding: null}, function(err, resp, body) {
var workbook = XLSX.read(body);

/* DO SOMETHING WITH workbook HERE */
});
``````

`axios` works the same way in browser and in NodeJS:

``````const XLSX = require("xlsx");
const axios = require("axios");

(async() => {
const res = await axios.get(url, {responseType: "arraybuffer"});
/* res.data is a Buffer */
const workbook = XLSX.read(res.data);

/* DO SOMETHING WITH workbook HERE */
})();
``````

Download files in an Electron app (click to show)

The `net` module in the main process can make HTTP/HTTPS requests to external resources. Responses should be manually concatenated using `Buffer.concat`:

``````const XLSX = require("xlsx");
const { net } = require("electron");

const req = net.request(url);
req.on("response", (res) => {
const bufs = []; // this array will collect all of the buffers
res.on("data", (chunk) => { bufs.push(chunk); });
res.on("end", () => {
const workbook = XLSX.read(Buffer.concat(bufs));

/* DO SOMETHING WITH workbook HERE */
});
});
req.end();
``````

Readable Streams in NodeJS (click to show)

When dealing with Readable Streams, the easiest approach is to buffer the stream and process the whole thing at the end:

``````var fs = require("fs");
var XLSX = require("xlsx");

function process_RS(stream, cb) {
var buffers = [];
stream.on("data", function(data) { buffers.push(data); });
stream.on("end", function() {
var buffer = Buffer.concat(buffers);
var workbook = XLSX.read(buffer, {type:"buffer"});

/* DO SOMETHING WITH workbook IN THE CALLBACK */
cb(workbook);
});
}
``````

ReadableStream in the browser (click to show)

When dealing with `ReadableStream`, the easiest approach is to buffer the stream and process the whole thing at the end:

``````// XLSX is a global from the standalone script

async function process_RS(stream) {
/* collect data */
const buffers = [];
for(;;) {
if(res.value) buffers.push(res.value);
if(res.done) break;
}

/* concat */
const out = new Uint8Array(buffers.reduce((acc, v) => acc + v.length, 0));

let off = 0;
for(const u8 of arr) {
out.set(u8, off);
off += u8.length;
}

return out;
}

const data = await process_RS(stream);
/* data is Uint8Array */
const workbook = XLSX.read(data);
``````

More detailed examples are covered in the included demos

### Processing JSON and JS Data

JSON and JS data tend to represent single worksheets. This section will use a few utility functions to generate workbooks:

Create a new Worksheet

``````var workbook = XLSX.utils.book_new();
``````

The `book_new` utility function creates an empty workbook with no worksheets.

Append a Worksheet to a Workbook

``````XLSX.utils.book_append_sheet(workbook, worksheet, sheet_name);
``````

The `book_append_sheet` utility function appends a worksheet to the workbook. The third argument specifies the desired worksheet name. Multiple worksheets can be added to a workbook by calling the function multiple times.

#### API

Create a worksheet from an array of arrays of JS values

``````var worksheet = XLSX.utils.aoa_to_sheet(aoa, opts);
``````

The `aoa_to_sheet` utility function walks an "array of arrays" in row-major order, generating a worksheet object. The following snippet generates a sheet with cell `A1` set to the string `A1`, cell `B1` set to `B2`, etc:

``````var worksheet = XLSX.utils.aoa_to_sheet([
["A1", "B1", "C1"],
["A2", "B2", "C2"],
["A3", "B3", "C3"]
])
``````

"Array of Arrays Input" describes the function and the optional `opts` argument in more detail.

Create a worksheet from an array of JS objects

``````var worksheet = XLSX.utils.json_to_sheet(jsa, opts);
``````

The `json_to_sheet` utility function walks an array of JS objects in order, generating a worksheet object. By default, it will generate a header row and one row per object in the array. The optional `opts` argument has settings to control the column order and header output.

"Array of Objects Input" describes the function and the optional `opts` argument in more detail.

#### Examples

"Zen of SheetJS" contains a detailed example "Get Data from a JSON Endpoint and Generate a Workbook"

The `database` demo includes examples of working with databases and query results.

### Processing HTML Tables

#### API

Create a worksheet by scraping an HTML TABLE in the page

``````var worksheet = XLSX.utils.table_to_sheet(dom_element, opts);
``````

The `table_to_sheet` utility function takes a DOM TABLE element and iterates through the rows to generate a worksheet. The `opts` argument is optional. "HTML Table Input" describes the function in more detail.

Create a workbook by scraping an HTML TABLE in the page

``````var workbook = XLSX.utils.table_to_book(dom_element, opts);
``````

The `table_to_book` utility function follows the same logic as `table_to_sheet`. After generating a worksheet, it creates a blank workbook and appends the spreadsheet.

The options argument supports the same options as `table_to_sheet`, with the addition of a `sheet` property to control the worksheet name. If the property is missing or no options are specified, the default name `Sheet1` is used.

#### Examples

Here are a few common scenarios (click on each subtitle to see the code):

HTML TABLE element in a webpage (click to show)

``````<!-- include the standalone script and shim.  this uses the UNPKG CDN -->
<script src="https://unpkg.com/xlsx/dist/shim.min.js"></script>
<script src="https://unpkg.com/xlsx/dist/xlsx.full.min.js"></script>

<!-- example table with id attribute -->
<table id="tableau">
<tr><td>Sheet</td><td>JS</td></tr>
<tr><td>12345</td><td>67</td></tr>
</table>

<!-- this block should appear after the table HTML and the standalone script -->
<script type="text/javascript">
var workbook = XLSX.utils.table_to_book(document.getElementById("tableau"));

/* DO SOMETHING WITH workbook HERE */
</script>
``````

Multiple tables on a web page can be converted to individual worksheets:

``````/* create new workbook */
var workbook = XLSX.utils.book_new();

/* convert table "table1" to worksheet named "Sheet1" */
var sheet1 = XLSX.utils.table_to_sheet(document.getElementById("table1"));
XLSX.utils.book_append_sheet(workbook, sheet1, "Sheet1");

/* convert table "table2" to worksheet named "Sheet2" */
var sheet2 = XLSX.utils.table_to_sheet(document.getElementById("table2"));
XLSX.utils.book_append_sheet(workbook, sheet2, "Sheet2");

/* workbook now has 2 worksheets */
``````

Alternatively, the HTML code can be extracted and parsed:

``````var htmlstr = document.getElementById("tableau").outerHTML;
var workbook = XLSX.read(htmlstr, {type:"string"});
``````

Chrome/Chromium Extension (click to show)

The `chrome` demo shows a complete example and details the required permissions and other settings.

In an extension, it is recommended to generate the workbook in a content script and pass the object back to the extension:

``````/* in the worker script */
chrome.runtime.onMessage.addListener(function(msg, sender, cb) {
/* pass a message like { sheetjs: true } from the extension to scrape */
if(!msg || !msg.sheetjs) return;
/* create a new workbook */
var workbook = XLSX.utils.book_new();
/* loop through each table element */
var tables = document.getElementsByTagName("table")
for(var i = 0; i < tables.length; ++i) {
var worksheet = XLSX.utils.table_to_sheet(tables[i]);
XLSX.utils.book_append_sheet(workbook, worksheet, "Table" + i);
}
/* pass back to the extension */
return cb(workbook);
});
``````

## Working with the Workbook

The full object format is described later in this README.

Reading a specific cell (click to show)

This example extracts the value stored in cell A1 from the first worksheet:

``````var first_sheet_name = workbook.SheetNames[0];
var address_of_cell = 'A1';

/* Get worksheet */
var worksheet = workbook.Sheets[first_sheet_name];

/* Find desired cell */
var desired_cell = worksheet[address_of_cell];

/* Get the value */
var desired_value = (desired_cell ? desired_cell.v : undefined);
``````

Adding a new worksheet to a workbook (click to show)

This example uses `XLSX.utils.aoa_to_sheet` to make a sheet and `XLSX.utils.book_append_sheet` to append the sheet to the workbook:

``````var ws_name = "SheetJS";

/* make worksheet */
var ws_data = [
[ "S", "h", "e", "e", "t", "J", "S" ],
[  1 ,  2 ,  3 ,  4 ,  5 ]
];
var ws = XLSX.utils.aoa_to_sheet(ws_data);

/* Add the worksheet to the workbook */
XLSX.utils.book_append_sheet(wb, ws, ws_name);
``````

Creating a new workbook from scratch (click to show)

The workbook object contains a `SheetNames` array of names and a `Sheets` object mapping sheet names to sheet objects. The `XLSX.utils.book_new` utility function creates a new workbook object:

``````/* create a new blank workbook */
var wb = XLSX.utils.book_new();
``````

The new workbook is blank and contains no worksheets. The write functions will error if the workbook is empty.

### Parsing and Writing Examples

https://sheetjs.com/demos/modify.html read + modify + write files

The node version installs a command line tool `xlsx` which can read spreadsheet files and output the contents in various formats. The source is available at `xlsx.njs` in the bin directory.

Some helper functions in `XLSX.utils` generate different views of the sheets:

• `XLSX.utils.sheet_to_csv` generates CSV
• `XLSX.utils.sheet_to_txt` generates UTF16 Formatted Text
• `XLSX.utils.sheet_to_html` generates HTML
• `XLSX.utils.sheet_to_json` generates an array of objects
• `XLSX.utils.sheet_to_formulae` generates a list of formulae

## Writing Workbooks

For writing, the first step is to generate output data. The helper functions `write` and `writeFile` will produce the data in various formats suitable for dissemination. The second step is to actual share the data with the end point. Assuming `workbook` is a workbook object:

nodejs write a file (click to show)

`XLSX.writeFile` uses `fs.writeFileSync` in server environments:

``````if(typeof require !== 'undefined') XLSX = require('xlsx');
/* output format determined by filename */
XLSX.writeFile(workbook, 'out.xlsb');
/* at this point, out.xlsb is a file that you can distribute */
``````

Photoshop ExtendScript write a file (click to show)

`writeFile` wraps the `File` logic in Photoshop and other ExtendScript targets. The specified path should be an absolute path:

``````#include "xlsx.extendscript.js"
/* output format determined by filename */
XLSX.writeFile(workbook, 'out.xlsx');
/* at this point, out.xlsx is a file that you can distribute */
``````

The `extendscript` demo includes a more complex example.

Browser add TABLE element to page (click to show)

The `sheet_to_html` utility function generates HTML code that can be added to any DOM element.

``````var worksheet = workbook.Sheets[workbook.SheetNames[0]];
var container = document.getElementById('tableau');
container.innerHTML = XLSX.utils.sheet_to_html(worksheet);
``````

Browser upload file (ajax) (click to show)

A complete example using XHR is included in the XHR demo, along with examples for fetch and wrapper libraries. This example assumes the server can handle Base64-encoded files (see the demo for a basic nodejs server):

``````/* in this example, send a base64 string to the server */
var wopts = { bookType:'xlsx', bookSST:false, type:'base64' };

var wbout = XLSX.write(workbook,wopts);

var req = new XMLHttpRequest();
var formdata = new FormData();
formdata.append('file', 'test.xlsx'); // <-- server expects `file` to hold name
formdata.append('data', wbout); // <-- `data` holds the base64-encoded data
req.send(formdata);
``````

Browser save file (click to show)

`XLSX.writeFile` wraps a few techniques for triggering a file save:

• `URL` browser API creates an object URL for the file, which the library uses by creating a link and forcing a click. It is supported in modern browsers.
• `msSaveBlob` is an IE10+ API for triggering a file save.
• `IE_FileSave` uses VBScript and ActiveX to write a file in IE6+ for Windows XP and Windows 7. The shim must be included in the containing HTML page.

There is no standard way to determine if the actual file has been downloaded.

``````/* output format determined by filename */
XLSX.writeFile(workbook, 'out.xlsb');
/* at this point, out.xlsb will have been downloaded */
``````

Browser save file (compatibility) (click to show)

`XLSX.writeFile` techniques work for most modern browsers as well as older IE. For much older browsers, there are workarounds implemented by wrapper libraries.

`FileSaver.js` implements `saveAs`. Note: `XLSX.writeFile` will automatically call `saveAs` if available.

``````/* bookType can be any supported output type */
var wopts = { bookType:'xlsx', bookSST:false, type:'array' };

var wbout = XLSX.write(workbook,wopts);

/* the saveAs call downloads a file on the local machine */
saveAs(new Blob([wbout],{type:"application/octet-stream"}), "test.xlsx");
``````

`Downloadify` uses a Flash SWF button to generate local files, suitable for environments where ActiveX is unavailable:

``````Downloadify.create(id,{
filename: "test.xlsx",
data: function() { return XLSX.write(wb, {bookType:"xlsx", type:'base64'}); },
append: false,
dataType: 'base64'
});
``````

The `oldie` demo shows an IE-compatible fallback scenario.

The included demos cover mobile apps and other special deployments.

### Streaming Write

The streaming write functions are available in the `XLSX.stream` object. They take the same arguments as the normal write functions but return a Readable Stream. They are only exposed in NodeJS.

• `XLSX.stream.to_csv` is the streaming version of `XLSX.utils.sheet_to_csv`.
• `XLSX.stream.to_html` is the streaming version of `XLSX.utils.sheet_to_html`.
• `XLSX.stream.to_json` is the streaming version of `XLSX.utils.sheet_to_json`.

nodejs convert to CSV and write file (click to show)

``````var output_file_name = "out.csv";
var stream = XLSX.stream.to_csv(worksheet);
stream.pipe(fs.createWriteStream(output_file_name));
``````

nodejs write JSON stream to screen (click to show)

``````/* to_json returns an object-mode stream */
var stream = XLSX.stream.to_json(worksheet, {raw:true});

/* the following stream converts JS objects to text via JSON.stringify */
var conv = new Transform({writableObjectMode:true});
conv._transform = function(obj, e, cb){ cb(null, JSON.stringify(obj) + "\n"); };

stream.pipe(conv); conv.pipe(process.stdout);
``````

https://github.com/sheetjs/sheetaki pipes write streams to nodejs response.

## Interface

`XLSX` is the exposed variable in the browser and the exported node variable

`XLSX.version` is the version of the library (added by the build script).

`XLSX.SSF` is an embedded version of the format library.

### Parsing functions

`XLSX.read(data, read_opts)` attempts to parse `data`.

`XLSX.readFile(filename, read_opts)` attempts to read `filename` and parse.

Parse options are described in the Parsing Options section.

### Writing functions

`XLSX.write(wb, write_opts)` attempts to write the workbook `wb`

`XLSX.writeFile(wb, filename, write_opts)` attempts to write `wb` to `filename`. In browser-based environments, it will attempt to force a client-side download.

`XLSX.writeFileAsync(wb, filename, o, cb)` attempts to write `wb` to `filename`. If `o` is omitted, the writer will use the third argument as the callback.

`XLSX.stream` contains a set of streaming write functions.

Write options are described in the Writing Options section.

### Utilities

Utilities are available in the `XLSX.utils` object and are described in the Utility Functions section:

Constructing:

• `book_new` creates an empty workbook
• `book_append_sheet` adds a worksheet to a workbook

Importing:

• `aoa_to_sheet` converts an array of arrays of JS data to a worksheet.
• `json_to_sheet` converts an array of JS objects to a worksheet.
• `table_to_sheet` converts a DOM TABLE element to a worksheet.
• `sheet_add_aoa` adds an array of arrays of JS data to an existing worksheet.
• `sheet_add_json` adds an array of JS objects to an existing worksheet.

Exporting:

• `sheet_to_json` converts a worksheet object to an array of JSON objects.
• `sheet_to_csv` generates delimiter-separated-values output.
• `sheet_to_txt` generates UTF16 formatted text.
• `sheet_to_html` generates HTML output.
• `sheet_to_formulae` generates a list of the formulae (with value fallbacks).

Cell and cell address manipulation:

• `format_cell` generates the text value for a cell (using number formats).
• `encode_row / decode_row` converts between 0-indexed rows and 1-indexed rows.
• `encode_col / decode_col` converts between 0-indexed columns and column names.
• `encode_cell / decode_cell` converts cell addresses.
• `encode_range / decode_range` converts cell ranges.

## Common Spreadsheet Format

SheetJS conforms to the Common Spreadsheet Format (CSF):

### General Structures

Cell address objects are stored as `{c:C, r:R}` where `C` and `R` are 0-indexed column and row numbers, respectively. For example, the cell address `B5` is represented by the object `{c:1, r:4}`.

Cell range objects are stored as `{s:S, e:E}` where `S` is the first cell and `E` is the last cell in the range. The ranges are inclusive. For example, the range `A3:B7` is represented by the object `{s:{c:0, r:2}, e:{c:1, r:6}}`. Utility functions perform a row-major order walk traversal of a sheet range:

``````for(var R = range.s.r; R <= range.e.r; ++R) {
for(var C = range.s.c; C <= range.e.c; ++C) {
var cell_address = {c:C, r:R};
/* if an A1-style address is needed, encode the address */
var cell_ref = XLSX.utils.encode_cell(cell_address);
}
}
``````

### Cell Object

Cell objects are plain JS objects with keys and values following the convention:

Built-in export utilities (such as the CSV exporter) will use the `w` text if it is available. To change a value, be sure to delete `cell.w` (or set it to `undefined`) before attempting to export. The utilities will regenerate the `w` text from the number format (`cell.z`) and the raw value if possible.

The actual array formula is stored in the `f` field of the first cell in the array range. Other cells in the range will omit the `f` field.

#### Data Types

The raw value is stored in the `v` value property, interpreted based on the `t` type property. This separation allows for representation of numbers as well as numeric text. There are 6 valid cell types:

Error values and interpretation (click to show)

Type `n` is the Number type. This includes all forms of data that Excel stores as numbers, such as dates/times and Boolean fields. Excel exclusively uses data that can be fit in an IEEE754 floating point number, just like JS Number, so the `v` field holds the raw number. The `w` field holds formatted text. Dates are stored as numbers by default and converted with `XLSX.SSF.parse_date_code`.

Type `d` is the Date type, generated only when the option `cellDates` is passed. Since JSON does not have a natural Date type, parsers are generally expected to store ISO 8601 Date strings like you would get from `date.toISOString()`. On the other hand, writers and exporters should be able to handle date strings and JS Date objects. Note that Excel disregards timezone modifiers and treats all dates in the local timezone. The library does not correct for this error.

Type `s` is the String type. Values are explicitly stored as text. Excel will interpret these cells as "number stored as text". Generated Excel files automatically suppress that class of error, but other formats may elicit errors.

Type `z` represents blank stub cells. They are generated in cases where cells have no assigned value but hold comments or other metadata. They are ignored by the core library data processing utility functions. By default these cells are not generated; the parser `sheetStubs` option must be set to `true`.

#### Dates

Excel Date Code details (click to show)

By default, Excel stores dates as numbers with a format code that specifies date processing. For example, the date `19-Feb-17` is stored as the number `42785` with a number format of `d-mmm-yy`. The `SSF` module understands number formats and performs the appropriate conversion.

XLSX also supports a special date type `d` where the data is an ISO 8601 date string. The formatter converts the date back to a number.

The default behavior for all parsers is to generate number cells. Setting `cellDates` to true will force the generators to store dates.

Time Zones and Dates (click to show)

Excel has no native concept of universal time. All times are specified in the local time zone. Excel limitations prevent specifying true absolute dates.

Following Excel, this library treats all dates as relative to local time zone.

Epochs: 1900 and 1904 (click to show)

Excel supports two epochs (January 1 1900 and January 1 1904). The workbook's epoch can be determined by examining the workbook's `wb.Workbook.WBProps.date1904` property:

``````!!(((wb.Workbook||{}).WBProps||{}).date1904)
``````

### Sheet Objects

Each key that does not start with `!` maps to a cell (using `A-1` notation)

`sheet[address]` returns the cell object for the specified address.

Special sheet keys (accessible as `sheet[key]`, each starting with `!`):

`sheet['!ref']`: A-1 based range representing the sheet range. Functions that work with sheets should use this parameter to determine the range. Cells that are assigned outside of the range are not processed. In particular, when writing a sheet by hand, cells outside of the range are not included

Functions that handle sheets should test for the presence of `!ref` field. If the `!ref` is omitted or is not a valid range, functions are free to treat the sheet as empty or attempt to guess the range. The standard utilities that ship with this library treat sheets as empty (for example, the CSV output is empty string).

When reading a worksheet with the `sheetRows` property set, the ref parameter will use the restricted range. The original range is set at `ws['!fullref']`

`sheet['!margins']`: Object representing the page margins. The default values follow Excel's "normal" preset. Excel also has a "wide" and a "narrow" preset but they are stored as raw measurements. The main properties are listed below:

Page margin details (click to show)

``````/* Set worksheet sheet to "normal" */
/* Set worksheet sheet to "wide" */
ws["!margins"]={left:1.0, right:1.0, top:1.0, bottom:1.0, header:0.5,footer:0.5}
/* Set worksheet sheet to "narrow" */
``````

#### Worksheet Object

In addition to the base sheet keys, worksheets also add:

`ws['!cols']`: array of column properties objects. Column widths are actually stored in files in a normalized manner, measured in terms of the "Maximum Digit Width" (the largest width of the rendered digits 0-9, in pixels). When parsed, the column objects store the pixel width in the `wpx` field, character width in the `wch` field, and the maximum digit width in the `MDW` field.

`ws['!rows']`: array of row properties objects as explained later in the docs. Each row object encodes properties including row height and visibility.

`ws['!merges']`: array of range objects corresponding to the merged cells in the worksheet. Plain text formats do not support merge cells. CSV export will write all cells in the merge range if they exist, so be sure that only the first cell (upper-left) in the range is set.

`ws['!outline']`: configure how outlines should behave. Options default to the default settings in Excel 2019:

• `ws['!protect']`: object of write sheet protection properties. The `password` key specifies the password for formats that support password-protected sheets (XLSX/XLSB/XLS). The writer uses the XOR obfuscation method. The following keys control the sheet protection -- set to `false` to enable a feature when sheet is locked or set to `true` to disable a feature:

Worksheet Protection Details (click to show)

• `ws['!autofilter']`: AutoFilter object following the schema:
``````type AutoFilter = {
ref:string; // A-1 based range representing the AutoFilter table range
}
``````

#### Chartsheet Object

Chartsheets are represented as standard sheets. They are distinguished with the `!type` property set to `"chart"`.

The underlying data and `!ref` refer to the cached data in the chartsheet. The first row of the chartsheet is the underlying header.

#### Macrosheet Object

Macrosheets are represented as standard sheets. They are distinguished with the `!type` property set to `"macro"`.

#### Dialogsheet Object

Dialogsheets are represented as standard sheets. They are distinguished with the `!type` property set to `"dialog"`.

### Workbook Object

`workbook.SheetNames` is an ordered list of the sheets in the workbook

`wb.Sheets[sheetname]` returns an object representing the worksheet.

`wb.Props` is an object storing the standard properties. `wb.Custprops` stores custom properties. Since the XLS standard properties deviate from the XLSX standard, XLS parsing stores core properties in both places.

`wb.Workbook` stores workbook-level attributes.

#### Workbook File Properties

The various file formats use different internal names for file properties. The workbook `Props` object normalizes the names:

File Properties (click to show)

For example, to set the workbook title property:

``````if(!wb.Props) wb.Props = {};
wb.Props.Title = "Insert Title Here";
``````

Custom properties are added in the workbook `Custprops` object:

``````if(!wb.Custprops) wb.Custprops = {};
wb.Custprops["Custom Property"] = "Custom Value";
``````

Writers will process the `Props` key of the options object:

``````/* force the Author to be "SheetJS" */
XLSX.write(wb, {Props:{Author:"SheetJS"}});
``````

### Workbook-Level Attributes

`wb.Workbook` stores workbook-level attributes.

#### Defined Names

`wb.Workbook.Names` is an array of defined name objects which have the keys:

Defined Name Properties (click to show)

Excel allows two sheet-scoped defined names to share the same name. However, a sheet-scoped name cannot collide with a workbook-scope name. Workbook writers may not enforce this constraint.

#### Workbook Views

`wb.Workbook.Views` is an array of workbook view objects which have the keys:

#### Miscellaneous Workbook Properties

`wb.Workbook.WBProps` holds other workbook properties:

### Document Features

Even for basic features like date storage, the official Excel formats store the same content in different ways. The parsers are expected to convert from the underlying file format representation to the Common Spreadsheet Format. Writers are expected to convert from CSF back to the underlying file format.

#### Formulae

The A1-style formula string is stored in the `f` field. Even though different file formats store the formulae in different ways, the formats are translated. Even though some formats store formulae with a leading equal sign, CSF formulae do not start with `=`.

Representation of A1=1, A2=2, A3=A1+A2 (click to show)

``````{
"!ref": "A1:A3",
A1: { t:'n', v:1 },
A2: { t:'n', v:2 },
A3: { t:'n', v:3, f:'A1+A2' }
}
``````

Shared formulae are decompressed and each cell has the formula corresponding to its cell. Writers generally do not attempt to generate shared formulae.

Cells with formula entries but no value will be serialized in a way that Excel and other spreadsheet tools will recognize. This library will not automatically compute formula results! For example, to compute `BESSELJ` in a worksheet:

Formula without known value (click to show)

``````{
"!ref": "A1:A3",
A1: { t:'n', v:3.14159 },
A2: { t:'n', v:2 },
A3: { t:'n', f:'BESSELJ(A1,A2)' }
}
``````

Array Formulae

Array formulae are stored in the top-left cell of the array block. All cells of an array formula have a `F` field corresponding to the range. A single-cell formula can be distinguished from a plain formula by the presence of `F` field.

Array Formula examples (click to show)

For example, setting the cell `C1` to the array formula `{=SUM(A1:A3*B1:B3)}`:

``````worksheet['C1'] = { t:'n', f: "SUM(A1:A3*B1:B3)", F:"C1:C1" };
``````

For a multi-cell array formula, every cell has the same array range but only the first cell specifies the formula. Consider `D1:D3=A1:A3*B1:B3`:

``````worksheet['D1'] = { t:'n', F:"D1:D3", f:"A1:A3*B1:B3" };
worksheet['D2'] = { t:'n', F:"D1:D3" };
worksheet['D3'] = { t:'n', F:"D1:D3" };
``````

Utilities and writers are expected to check for the presence of a `F` field and ignore any possible formula element `f` in cells other than the starting cell. They are not expected to perform validation of the formulae!

Formula Output Utility Function (click to show)

The `sheet_to_formulae` method generates one line per formula or array formula. Array formulae are rendered in the form `range=formula` while plain cells are rendered in the form `cell=formula or value`. Note that string literals are prefixed with an apostrophe `'`, consistent with Excel's formula bar display.

Formulae File Format Details (click to show)

Since Excel prohibits named cells from colliding with names of A1 or RC style cell references, a (not-so-simple) regex conversion is possible. BIFF Parsed formulae and Lotus Parsed formulae have to be explicitly unwound. OpenFormula formulae can be converted with regular expressions.

#### Row and Column Properties

Format Support (click to show)

Row Properties: XLSX/M, XLSB, BIFF8 XLS, XLML, SYLK, DOM, ODS

Column Properties: XLSX/M, XLSB, BIFF8 XLS, XLML, SYLK, DOM

Row and Column properties are not extracted by default when reading from a file and are not persisted by default when writing to a file. The option `cellStyles: true` must be passed to the relevant read or write function.

Column Properties

The `!cols` array in each worksheet, if present, is a collection of `ColInfo` objects which have the following properties:

``````type ColInfo = {
/* visibility */
hidden?: boolean; // if true, the column is hidden

/* column width is specified in one of the following ways: */
wpx?:    number;  // width in screen pixels
width?:  number;  // width in Excel's "Max Digit Width", width*256 is integral
wch?:    number;  // width in characters

/* other fields for preserving features from files */
level?:  number;  // 0-indexed outline / group level
MDW?:    number;  // Excel's "Max Digit Width" unit, always integral
};
``````

Row Properties

The `!rows` array in each worksheet, if present, is a collection of `RowInfo` objects which have the following properties:

``````type RowInfo = {
/* visibility */
hidden?: boolean; // if true, the row is hidden

/* row height is specified in one of the following ways: */
hpx?:    number;  // height in screen pixels
hpt?:    number;  // height in points

level?:  number;  // 0-indexed outline / group level
};
``````

Outline / Group Levels Convention

The Excel UI displays the base outline level as `1` and the max level as `8`. Following JS conventions, SheetJS uses 0-indexed outline levels wherein the base outline level is `0` and the max level is `7`.

Why are there three width types? (click to show)

There are three different width types corresponding to the three different ways spreadsheets store column widths:

SYLK and other plain text formats use raw character count. Contemporaneous tools like Visicalc and Multiplan were character based. Since the characters had the same width, it sufficed to store a count. This tradition was continued into the BIFF formats.

SpreadsheetML (2003) tried to align with HTML by standardizing on screen pixel count throughout the file. Column widths, row heights, and other measures use pixels. When the pixel and character counts do not align, Excel rounds values.

XLSX internally stores column widths in a nebulous "Max Digit Width" form. The Max Digit Width is the width of the largest digit when rendered (generally the "0" character is the widest). The internal width must be an integer multiple of the the width divided by 256. ECMA-376 describes a formula for converting between pixels and the internal width. This represents a hybrid approach.

Read functions attempt to populate all three properties. Write functions will try to cycle specified values to the desired type. In order to avoid potential conflicts, manipulation should delete the other properties first. For example, when changing the pixel width, delete the `wch` and `width` properties.

Implementation details (click to show)

Row Heights

Excel internally stores row heights in points. The default resolution is 72 DPI or 96 PPI, so the pixel and point size should agree. For different resolutions they may not agree, so the library separates the concepts.

Even though all of the information is made available, writers are expected to follow the priority order:

1. use `hpx` pixel height if available
2. use `hpt` point height if available

Column Widths

Given the constraints, it is possible to determine the MDW without actually inspecting the font! The parsers guess the pixel width by converting from width to pixels and back, repeating for all possible MDW and selecting the MDW that minimizes the error. XLML actually stores the pixel width, so the guess works in the opposite direction.

Even though all of the information is made available, writers are expected to follow the priority order:

1. use `width` field if available
2. use `wpx` pixel width if available
3. use `wch` character count if available

#### Number Formats

The `cell.w` formatted text for each cell is produced from `cell.v` and `cell.z` format. If the format is not specified, the Excel `General` format is used. The format can either be specified as a string or as an index into the format table. Parsers are expected to populate `workbook.SSF` with the number format table. Writers are expected to serialize the table.

Custom tools should ensure that the local table has each used format string somewhere in the table. Excel convention mandates that the custom formats start at index 164. The following example creates a custom format from scratch:

New worksheet with custom format (click to show)

``````var wb = {
SheetNames: ["Sheet1"],
Sheets: {
Sheet1: {
"!ref":"A1:C1",
A1: { t:"n", v:10000 },                    // <-- General format
B1: { t:"n", v:10000, z: "0%" },           // <-- Builtin format
C1: { t:"n", v:10000, z: "\"T\"\ #0.00" }  // <-- Custom format
}
}
}
``````

The rules are slightly different from how Excel displays custom number formats. In particular, literal characters must be wrapped in double quotes or preceded by a backslash. For more info, see the Excel documentation article `Create or delete a custom number format` or ECMA-376 18.8.31 (Number Formats)

Default Number Formats (click to show)

The default formats are listed in ECMA-376 18.8.30:

Format 14 (`m/d/yy`) is localized by Excel: even though the file specifies that number format, it will be drawn differently based on system settings. It makes sense when the producer and consumer of files are in the same locale, but that is not always the case over the Internet. To get around this ambiguity, parse functions accept the `dateNF` option to override the interpretation of that specific format string.

Format Support (click to show)

Cell Hyperlinks: XLSX/M, XLSB, BIFF8 XLS, XLML, ODS

Tooltips: XLSX/M, XLSB, BIFF8 XLS, XLML

Hyperlinks are stored in the `l` key of cell objects. The `Target` field of the hyperlink object is the target of the link, including the URI fragment. Tooltips are stored in the `Tooltip` field and are displayed when you move your mouse over the text.

For example, the following snippet creates a link from cell `A3` to https://sheetjs.com with the tip `"Find us @ SheetJS.com!"`:

``````ws['A1'].l = { Target:"https://sheetjs.com", Tooltip:"Find us @ SheetJS.com!" };
``````

Note that Excel does not automatically style hyperlinks -- they will generally be displayed as normal text.

HTTP / HTTPS links can be used directly:

``````ws['A2'].l = { Target:"https://docs.sheetjs.com/#hyperlinks" };
ws['A3'].l = { Target:"http://localhost:7262/yes_localhost_works" };
``````

Excel also supports `mailto` email links with subject line:

``````ws['A4'].l = { Target:"mailto:ignored@dev.null" };
ws['A5'].l = { Target:"mailto:ignored@dev.null?subject=Test Subject" };
``````

Links to absolute paths should use the `file://` URI scheme:

``````ws['B1'].l = { Target:"file:///SheetJS/t.xlsx" }; /* Link to /SheetJS/t.xlsx */
ws['B2'].l = { Target:"file:///c:/SheetJS.xlsx" }; /* Link to c:\SheetJS.xlsx */
``````

Links to relative paths can be specified without a scheme:

``````ws['B3'].l = { Target:"SheetJS.xlsb" }; /* Link to SheetJS.xlsb */
ws['B4'].l = { Target:"../SheetJS.xlsm" }; /* Link to ../SheetJS.xlsm */
``````

Relative Paths have undefined behavior in the SpreadsheetML 2003 format. Excel 2019 will treat a `..\` parent mark as two levels up.

Links where the target is a cell or range or defined name in the same workbook ("Internal Links") are marked with a leading hash character:

``````ws['C1'].l = { Target:"#E2" }; /* Link to cell E2 */
ws['C2'].l = { Target:"#Sheet2!E2" }; /* Link to cell E2 in sheet Sheet2 */
ws['C3'].l = { Target:"#SomeDefinedName" }; /* Link to Defined Name */
``````

Cell comments are objects stored in the `c` array of cell objects. The actual contents of the comment are split into blocks based on the comment author. The `a` field of each comment object is the author of the comment and the `t` field is the plain text representation.

For example, the following snippet appends a cell comment into cell `A1`:

``````if(!ws.A1.c) ws.A1.c = [];
ws.A1.c.push({a:"SheetJS", t:"I'm a little comment, short and stout!"});
``````

Note: XLSB enforces a 54 character limit on the Author name. Names longer than 54 characters may cause issues with other formats.

To mark a comment as normally hidden, set the `hidden` property:

``````if(!ws.A1.c) ws.A1.c = [];
ws.A1.c.push({a:"SheetJS", t:"This comment is visible"});

if(!ws.A2.c) ws.A2.c = [];
ws.A2.c.hidden = true;
ws.A2.c.push({a:"SheetJS", t:"This comment will be hidden"});
``````

#### Sheet Visibility

Excel enables hiding sheets in the lower tab bar. The sheet data is stored in the file but the UI does not readily make it available. Standard hidden sheets are revealed in the "Unhide" menu. Excel also has "very hidden" sheets which cannot be revealed in the menu. It is only accessible in the VB Editor!

The visibility setting is stored in the `Hidden` property of sheet props array.

More details (click to show)

``````> wb.Workbook.Sheets.map(function(x) { return [x.name, x.Hidden] })
[ [ 'Visible', 0 ], [ 'Hidden', 1 ], [ 'VeryHidden', 2 ] ]
``````

Non-Excel formats do not support the Very Hidden state. The best way to test if a sheet is visible is to check if the `Hidden` property is logical truth:

``````> wb.Workbook.Sheets.map(function(x) { return [x.name, !x.Hidden] })
[ [ 'Visible', true ], [ 'Hidden', false ], [ 'VeryHidden', false ] ]
``````

#### VBA and Macros

VBA Macros are stored in a special data blob that is exposed in the `vbaraw` property of the workbook object when the `bookVBA` option is `true`. They are supported in `XLSM`, `XLSB`, and `BIFF8 XLS` formats. The supported format writers automatically insert the data blobs if it is present in the workbook and associate with the worksheet names.

Custom Code Names (click to show)

The workbook code name is stored in `wb.Workbook.WBProps.CodeName`. By default, Excel will write `ThisWorkbook` or a translated phrase like `DieseArbeitsmappe`. Worksheet and Chartsheet code names are in the worksheet properties object at `wb.Workbook.Sheets[i].CodeName`. Macrosheets and Dialogsheets are ignored.

The readers and writers preserve the code names, but they have to be manually set when adding a VBA blob to a different workbook.

Macrosheets (click to show)

Older versions of Excel also supported a non-VBA "macrosheet" sheet type that stored automation commands. These are exposed in objects with the `!type` property set to `"macro"`.

Detecting macros in workbooks (click to show)

The `vbaraw` field will only be set if macros are present, so testing is simple:

``````function wb_has_macro(wb/*:workbook*/)/*:boolean*/ {
if(!!wb.vbaraw) return true;
const sheets = wb.SheetNames.map((n) => wb.Sheets[n]);
return sheets.some((ws) => !!ws && ws['!type']=='macro');
}
``````

## Parsing Options

The exported `read` and `readFile` functions accept an options argument:

• Even if `cellNF` is false, formatted text will be generated and saved to `.w`
• In some cases, sheets may be parsed even if `bookSheets` is false.
• Excel aggressively tries to interpret values from CSV and other plain text. This leads to surprising behavior! The `raw` option suppresses value parsing.
• `bookSheets` and `bookProps` combine to give both sets of information
• `Deps` will be an empty object if `bookDeps` is false
• `bookFiles` behavior depends on file type:
• `keys` array (paths in the ZIP) for ZIP-based formats
• `files` hash (mapping paths to objects representing the files) for ZIP
• `cfb` object for formats using CFB containers
• `sheetRows-1` rows will be generated when looking at the JSON object output (since the header row is counted as a row when parsing the data)
• By default all worksheets are parsed. `sheets` restricts based on input type:
• number: zero-based index of worksheet to parse (`0` is first worksheet)
• string: name of worksheet to parse (case insensitive)
• array of numbers and strings to select multiple worksheets.
• `bookVBA` merely exposes the raw VBA CFB object. It does not parse the data. XLSM and XLSB store the VBA CFB object in `xl/vbaProject.bin`. BIFF8 XLS mixes the VBA entries alongside the core Workbook entry, so the library generates a new XLSB-compatible blob from the XLS CFB container.
• `codepage` is applied to BIFF2 - BIFF5 files without `CodePage` records and to CSV files without BOM in `type:"binary"`. BIFF8 XLS always defaults to 1200.
• `PRN` affects parsing of text files without a common delimiter character.
• Currently only XOR encryption is supported. Unsupported error will be thrown for files employing other encryption methods.
• Newer Excel functions are serialized with the `_xlfn.` prefix, hidden from the user. SheetJS will strip `_xlfn.` normally. The `xlfn` option preserves them.
• WTF is mainly for development. By default, the parser will suppress read errors on single worksheets, allowing you to read from the worksheets that do parse properly. Setting `WTF:true` forces those errors to be thrown.

### Input Type

Strings can be interpreted in multiple ways. The `type` parameter for `read` tells the library how to parse the data argument:

### Guessing File Type

Implementation Details (click to show)

Excel and other spreadsheet tools read the first few bytes and apply other heuristics to determine a file type. This enables file type punning: renaming files with the `.xls` extension will tell your computer to use Excel to open the file but Excel will know how to handle it. This library applies similar logic:

DBF files are detected based on the first byte as well as the third and fourth bytes (corresponding to month and day of the file date)

Works for Windows files are detected based on the BOF record with type `0xFF`

Plain text format guessing follows the priority order:

• HTML tags include: `html`, `table`, `head`, `meta`, `script`, `style`, `div`

Why are random text files valid? (click to show)

Excel is extremely aggressive in reading files. Adding an XLS extension to any display text file (where the only characters are ANSI display chars) tricks Excel into thinking that the file is potentially a CSV or TSV file, even if it is only one column! This library attempts to replicate that behavior.

The best approach is to validate the desired worksheet and ensure it has the expected number of rows or columns. Extracting the range is extremely simple:

``````var range = XLSX.utils.decode_range(worksheet['!ref']);
var ncols = range.e.c - range.s.c + 1, nrows = range.e.r - range.s.r + 1;
``````

## Writing Options

The exported `write` and `writeFile` functions accept an options argument:

• `bookSST` is slower and more memory intensive, but has better compatibility with older versions of iOS Numbers
• The raw data is the only thing guaranteed to be saved. Features not described in this README may not be serialized.
• `cellDates` only applies to XLSX output and is not guaranteed to work with third-party readers. Excel itself does not usually write cells with type `d` so non-Excel tools may ignore the data or error in the presence of dates.
• `Props` is an object mirroring the workbook `Props` field. See the table from the Workbook File Properties section.
• if specified, the string from `themeXLSX` will be saved as the primary theme for XLSX/XLSB/XLSM files (to `xl/theme/theme1.xml` in the ZIP)
• Due to a bug in the program, some features like "Text to Columns" will crash Excel on worksheets where error conditions are ignored. The writer will mark files to ignore the error by default. Set `ignoreEC` to `false` to suppress.

### Supported Output Formats

For broad compatibility with third-party tools, this library supports many output formats. The specific file type is controlled with `bookType` option:

• `compression` only applies to formats with ZIP containers.
• Formats that only support a single sheet require a `sheet` option specifying the worksheet. If the string is empty, the first worksheet is used.
• `writeFile` will automatically guess the output file format based on the file extension if `bookType` is not specified. It will choose the first format in the aforementioned table that matches the extension.

### Output Type

The `type` argument for `write` mirrors the `type` argument for `read`:

## Utility Functions

The `sheet_to_*` functions accept a worksheet and an optional options object.

The `*_to_sheet` functions accept a data object and an optional options object.

The examples are based on the following worksheet:

``````XXX| A | B | C | D | E | F | G |
---+---+---+---+---+---+---+---+
1 | S | h | e | e | t | J | S |
2 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
3 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
``````

### Array of Arrays Input

`XLSX.utils.aoa_to_sheet` takes an array of arrays of JS values and returns a worksheet resembling the input data. Numbers, Booleans and Strings are stored as the corresponding styles. Dates are stored as date or numbers. Array holes and explicit `undefined` values are skipped. `null` values may be stubbed. All other values are stored as strings. The function takes an options argument:

Examples (click to show)

To generate the example sheet:

``````var ws = XLSX.utils.aoa_to_sheet([
"SheetJS".split(""),
[1,2,3,4,5,6,7],
[2,3,4,5,6,7,8]
]);
``````

`XLSX.utils.sheet_add_aoa` takes an array of arrays of JS values and updates an existing worksheet object. It follows the same process as `aoa_to_sheet` and accepts an options argument:

`origin` is expected to be one of:

Examples (click to show)

Consider the worksheet:

``````XXX| A | B | C | D | E | F | G |
---+---+---+---+---+---+---+---+
1 | S | h | e | e | t | J | S |
2 | 1 | 2 |   |   | 5 | 6 | 7 |
3 | 2 | 3 |   |   | 6 | 7 | 8 |
4 | 3 | 4 |   |   | 7 | 8 | 9 |
5 | 4 | 5 | 6 | 7 | 8 | 9 | 0 |
``````

This worksheet can be built up in the order `A1:G1, A2:B4, E2:G4, A5:G5`:

``````/* Initial row */
var ws = XLSX.utils.aoa_to_sheet([ "SheetJS".split("") ]);

/* Write data starting at A2 */
XLSX.utils.sheet_add_aoa(ws, [[1,2], [2,3], [3,4]], {origin: "A2"});

/* Write data starting at E2 */
XLSX.utils.sheet_add_aoa(ws, [[5,6,7], [6,7,8], [7,8,9]], {origin:{r:1, c:4}});

/* Append row */
XLSX.utils.sheet_add_aoa(ws, [[4,5,6,7,8,9,0]], {origin: -1});
``````

### Array of Objects Input

`XLSX.utils.json_to_sheet` takes an array of objects and returns a worksheet with automatically-generated "headers" based on the keys of the objects. The default column order is determined by the first appearance of the field using `Object.keys`. The function accepts an options argument:

• All fields from each row will be written. If `header` is an array and it does not contain a particular field, the key will be appended to the array.
• Cell types are deduced from the type of each value. For example, a `Date` object will generate a Date cell, while a string will generate a Text cell.
• Null values will be skipped by default. If `nullError` is true, an error cell corresponding to `#NULL!` will be written to the worksheet.

Examples (click to show)

The original sheet cannot be reproduced using plain objects since JS object keys must be unique. After replacing the second `e` and `S` with `e_1` and `S_1`:

``````var ws = XLSX.utils.json_to_sheet([
{ S:1, h:2, e:3, e_1:4, t:5, J:6, S_1:7 },
{ S:2, h:3, e:4, e_1:5, t:6, J:7, S_1:8 }
``````

Alternatively, the header row can be skipped:

``````var ws = XLSX.utils.json_to_sheet([
{ A:"S", B:"h", C:"e", D:"e", E:"t", F:"J", G:"S" },
{ A: 1,  B: 2,  C: 3,  D: 4,  E: 5,  F: 6,  G: 7  },
{ A: 2,  B: 3,  C: 4,  D: 5,  E: 6,  F: 7,  G: 8  }
``````

`XLSX.utils.sheet_add_json` takes an array of objects and updates an existing worksheet object. It follows the same process as `json_to_sheet` and accepts an options argument:

`origin` is expected to be one of:

Examples (click to show)

Consider the worksheet:

``````XXX| A | B | C | D | E | F | G |
---+---+---+---+---+---+---+---+
1 | S | h | e | e | t | J | S |
2 | 1 | 2 |   |   | 5 | 6 | 7 |
3 | 2 | 3 |   |   | 6 | 7 | 8 |
4 | 3 | 4 |   |   | 7 | 8 | 9 |
5 | 4 | 5 | 6 | 7 | 8 | 9 | 0 |
``````

This worksheet can be built up in the order `A1:G1, A2:B4, E2:G4, A5:G5`:

``````/* Initial row */
var ws = XLSX.utils.json_to_sheet([
{ A: "S", B: "h", C: "e", D: "e", E: "t", F: "J", G: "S" }
], {header: ["A", "B", "C", "D", "E", "F", "G"], skipHeader: true});

/* Write data starting at A2 */
{ A: 1, B: 2 }, { A: 2, B: 3 }, { A: 3, B: 4 }
], {skipHeader: true, origin: "A2"});

/* Write data starting at E2 */
{ A: 5, B: 6, C: 7 }, { A: 6, B: 7, C: 8 }, { A: 7, B: 8, C: 9 }
], {skipHeader: true, origin: { r: 1, c: 4 }, header: [ "A", "B", "C" ]});

/* Append row */
{ A: 4, B: 5, C: 6, D: 7, E: 8, F: 9, G: 0 }
], {header: ["A", "B", "C", "D", "E", "F", "G"], skipHeader: true, origin: -1});
``````

### HTML Table Input

`XLSX.utils.table_to_sheet` takes a table DOM element and returns a worksheet resembling the input table. Numbers are parsed. All other data will be stored as strings.

`XLSX.utils.table_to_book` produces a minimal workbook based on the worksheet.

Both functions accept options arguments:

Examples (click to show)

To generate the example sheet, start with the HTML table:

``````<table id="sheetjs">
<tr><td>S</td><td>h</td><td>e</td><td>e</td><td>t</td><td>J</td><td>S</td></tr>
<tr><td>1</td><td>2</td><td>3</td><td>4</td><td>5</td><td>6</td><td>7</td></tr>
<tr><td>2</td><td>3</td><td>4</td><td>5</td><td>6</td><td>7</td><td>8</td></tr>
</table>
``````

To process the table:

``````var tbl = document.getElementById('sheetjs');
var wb = XLSX.utils.table_to_book(tbl);
``````

Note: `XLSX.read` can handle HTML represented as strings.

`XLSX.utils.sheet_add_dom` takes a table DOM element and updates an existing worksheet object. It follows the same process as `table_to_sheet` and accepts an options argument:

`origin` is expected to be one of:

Examples (click to show)

A small helper function can create gap rows between tables:

``````function create_gap_rows(ws, nrows) {
var ref = XLSX.utils.decode_range(ws["!ref"]);       // get original range
ref.e.r += nrows;                                    // add to ending row
ws["!ref"] = XLSX.utils.encode_range(ref);           // reassign row
}

/* first table */
var ws = XLSX.utils.table_to_sheet(document.getElementById('table1'));
create_gap_rows(ws, 1); // one row gap after first table

/* second table */
XLSX.utils.sheet_add_dom(ws, document.getElementById('table2'), {origin: -1});
create_gap_rows(ws, 3); // three rows gap after second table

/* third table */
XLSX.utils.sheet_add_dom(ws, document.getElementById('table3'), {origin: -1});
``````

### Formulae Output

`XLSX.utils.sheet_to_formulae` generates an array of commands that represent how a person would enter data into an application. Each entry is of the form `A1-cell-address=formula-or-value`. String literals are prefixed with a `'` in accordance with Excel.

Examples (click to show)

For the example sheet:

``````> var o = XLSX.utils.sheet_to_formulae(ws);
> [o[0], o[5], o[10], o[15], o[20]];
[ 'A1=\'S', 'F1=\'J', 'D2=4', 'B3=3', 'G3=8' ]
``````

### Delimiter-Separated Output

As an alternative to the `writeFile` CSV type, `XLSX.utils.sheet_to_csv` also produces CSV output. The function takes an options argument:

• `strip` will remove trailing commas from each line under default `FS/RS`
• `blankrows` must be set to `false` to skip blank lines.
• Fields containing the record or field separator will automatically be wrapped in double quotes; `forceQuotes` forces all cells to be wrapped in quotes.

Examples (click to show)

For the example sheet:

``````> console.log(XLSX.utils.sheet_to_csv(ws));
S,h,e,e,t,J,S
1,2,3,4,5,6,7
2,3,4,5,6,7,8
> console.log(XLSX.utils.sheet_to_csv(ws, {FS:"\t"}));
S    h    e    e    t    J    S
1    2    3    4    5    6    7
2    3    4    5    6    7    8
> console.log(XLSX.utils.sheet_to_csv(ws,{FS:":",RS:"|"}));
S:h:e:e:t:J:S|1:2:3:4:5:6:7|2:3:4:5:6:7:8|
``````

#### UTF-16 Unicode Text

The `txt` output type uses the tab character as the field separator. If the `codepage` library is available (included in full distribution but not core), the output will be encoded in `CP1200` and the BOM will be prepended.

`XLSX.utils.sheet_to_txt` takes the same arguments as `sheet_to_csv`.

### HTML Output

As an alternative to the `writeFile` HTML type, `XLSX.utils.sheet_to_html` also produces HTML output. The function takes an options argument:

Examples (click to show)

For the example sheet:

``````> console.log(XLSX.utils.sheet_to_html(ws));
// ...
``````

### JSON

`XLSX.utils.sheet_to_json` generates different types of JS objects. The function takes an options argument:

• `raw` only affects cells which have a format code (`.z`) field or a formatted text (`.w`) field.
• If `header` is specified, the first row is considered a data row; if `header` is not specified, the first row is the header row and not considered data.
• When `header` is not specified, the conversion will automatically disambiguate header entries by affixing `_` and a count starting at `1`. For example, if three columns have header `foo` the output fields are `foo`, `foo_1`, `foo_2`
• `null` values are returned when `raw` is true but are skipped when false.
• If `defval` is not specified, null and undefined values are skipped normally. If specified, all null and undefined points will be filled with `defval`
• When `header` is `1`, the default is to generate blank rows. `blankrows` must be set to `false` to skip blank rows.
• When `header` is not `1`, the default is to skip blank rows. `blankrows` must be true to generate blank rows

`range` is expected to be one of:

`header` is expected to be one of:

If header is not `1`, the row object will contain the non-enumerable property `__rowNum__` that represents the row of the sheet corresponding to the entry.

Examples (click to show)

For the example sheet:

``````> XLSX.utils.sheet_to_json(ws);
[ { S: 1, h: 2, e: 3, e_1: 4, t: 5, J: 6, S_1: 7 },
{ S: 2, h: 3, e: 4, e_1: 5, t: 6, J: 7, S_1: 8 } ]

[ { A: 'S', B: 'h', C: 'e', D: 'e', E: 't', F: 'J', G: 'S' },
{ A: '1', B: '2', C: '3', D: '4', E: '5', F: '6', G: '7' },
{ A: '2', B: '3', C: '4', D: '5', E: '6', F: '7', G: '8' } ]

[ { '6': 'J', '9': 'S', A: 'S', E: 'h', I: 'e', O: 'e', U: 't' },
{ '6': '6', '9': '7', A: '1', E: '2', I: '3', O: '4', U: '5' },
{ '6': '7', '9': '8', A: '2', E: '3', I: '4', O: '5', U: '6' } ]

[ [ 'S', 'h', 'e', 'e', 't', 'J', 'S' ],
[ '1', '2', '3', '4', '5', '6', '7' ],
[ '2', '3', '4', '5', '6', '7', '8' ] ]
``````

Example showing the effect of `raw`:

``````> ws['A2'].w = "3";                          // set A2 formatted string value

> XLSX.utils.sheet_to_json(ws, {header:1, raw:false});
[ [ 'S', 'h', 'e', 'e', 't', 'J', 'S' ],
[ '3', '2', '3', '4', '5', '6', '7' ],     // <-- A2 uses the formatted string
[ '2', '3', '4', '5', '6', '7', '8' ] ]

[ [ 'S', 'h', 'e', 'e', 't', 'J', 'S' ],
[ 1, 2, 3, 4, 5, 6, 7 ],                   // <-- A2 uses the raw value
[ 2, 3, 4, 5, 6, 7, 8 ] ]
``````

## File Formats

Despite the library name `xlsx`, it supports numerous spreadsheet file formats:

Features not supported by a given file format will not be written. Formats with range limits will be silently truncated:

Excel 2003 SpreadsheetML range limits are governed by the version of Excel and are not enforced by the writer.

File Format Details (click to show)

• Excel 2007+ XML (XLSX/XLSM)

XLSX and XLSM files are ZIP containers containing a series of XML files in accordance with the Open Packaging Conventions (OPC). The XLSM format, almost identical to XLSX, is used for files containing macros.

The format is standardized in ECMA-376 and later in ISO/IEC 29500. Excel does not follow the specification, and there are additional documents discussing how Excel deviates from the specification.

• Excel 2.0-95 (BIFF2/BIFF3/BIFF4/BIFF5)

BIFF 2/3 XLS are single-sheet streams of binary records. Excel 4 introduced the concept of a workbook (`XLW` files) but also had single-sheet `XLS` format. The structure is largely similar to the Lotus 1-2-3 file formats. BIFF5/8/12 extended the format in various ways but largely stuck to the same record format.

There is no official specification for any of these formats. Excel 95 can write files in these formats, so record lengths and fields were determined by writing in all of the supported formats and comparing files. Excel 2016 can generate BIFF5 files, enabling a full suite of file tests starting from XLSX or BIFF2.

• Excel 97-2004 Binary (BIFF8)

BIFF8 exclusively uses the Compound File Binary container format, splitting some content into streams within the file. At its core, it still uses an extended version of the binary record format from older versions of BIFF.

The `MS-XLS` specification covers the basics of the file format, and other specifications expand on serialization of features like properties.

• Excel 2003-2004 (SpreadsheetML)

Predating XLSX, SpreadsheetML files are simple XML files. There is no official and comprehensive specification, although MS has released documentation on the format. Since Excel 2016 can generate SpreadsheetML files, mapping features is pretty straightforward.

• Excel 2007+ Binary (XLSB, BIFF12)

Introduced in parallel with XLSX, the XLSB format combines the BIFF architecture with the content separation and ZIP container of XLSX. For the most part nodes in an XLSX sub-file can be mapped to XLSB records in a corresponding sub-file.

The `MS-XLSB` specification covers the basics of the file format, and other specifications expand on serialization of features like properties.

• Delimiter-Separated Values (CSV/TXT)

Excel CSV deviates from RFC4180 in a number of important ways. The generated CSV files should generally work in Excel although they may not work in RFC4180 compatible readers. The parser should generally understand Excel CSV. The writer proactively generates cells for formulae if values are unavailable.

Excel TXT uses tab as the delimiter and code page 1200.

Like in Excel, files starting with `0x49 0x44 ("ID")` are treated as Symbolic Link files. Unlike Excel, if the file does not have a valid SYLK header, it will be proactively reinterpreted as CSV. There are some files with semicolon delimiter that align with a valid SYLK file. For the broadest compatibility, all cells with the value of `ID` are automatically wrapped in double-quotes.

Miscellaneous Workbook Formats

Support for other formats is generally far behind XLS/XLSB/XLSX support, due in part to a lack of publicly available documentation. Test files were produced in the respective apps and compared to their XLS exports to determine structure. The main focus is data extraction.

• Lotus 1-2-3 (WKS/WK1/WK2/WK3/WK4/123)

The Lotus formats consist of binary records similar to the BIFF structure. Lotus did release a specification decades ago covering the original WK1 format. Other features were deduced by producing files and comparing to Excel support.

Generated WK1 worksheets are compatible with Lotus 1-2-3 R2 and Excel 5.0.

Generated WK3 workbooks are compatible with Lotus 1-2-3 R9 and Excel 5.0.

• Quattro Pro (WQ1/WQ2/WB1/WB2/WB3/QPW)

The Quattro Pro formats use binary records in the same way as BIFF and Lotus. Some of the newer formats (namely WB3 and QPW) use a CFB enclosure just like BIFF8 XLS.

• Works for DOS / Windows Spreadsheet (WKS/XLR)

All versions of Works were limited to a single worksheet.

Works for DOS 1.x - 3.x and Works for Windows 2.x extends the Lotus WKS format with additional record types.

Works for Windows 3.x - 5.x uses the same format and WKS extension. The BOF record has type `FF`

Works for Windows 6.x - 9.x use the XLR format. XLR is nearly identical to BIFF8 XLS: it uses the CFB container with a Workbook stream. Works 9 saves the exact Workbook stream for the XLR and the 97-2003 XLS export. Works 6 XLS includes two empty worksheets but the main worksheet has an identical encoding. XLR also includes a `WksSSWorkBook` stream similar to Lotus FM3/FMT files.

• Numbers 3.0+ / iWork 2013+ Spreadsheet (NUMBERS)

iWork 2013 (Numbers 3.0 / Pages 5.0 / Keynote 6.0) switched from a proprietary XML-based format to the current file format based on the iWork Archive (IWA). This format has been used up through the current release (Numbers 11.2).

The parser focuses on extracting raw data from tables. Numbers technically supports multiple tables in a logical worksheet, including custom titles. This parser will generate one worksheet per Numbers table.

• OpenDocument Spreadsheet (ODS/FODS)

ODS is an XML-in-ZIP format akin to XLSX while FODS is an XML format akin to SpreadsheetML. Both are detailed in the OASIS standard, but tools like LO/OO add undocumented extensions. The parsers and writers do not implement the full standard, instead focusing on parts necessary to extract and store raw data.

• Uniform Office Spreadsheet (UOS1/2)

UOS is a very similar format, and it comes in 2 varieties corresponding to ODS and FODS respectively. For the most part, the difference between the formats is in the names of tags and attributes.

Miscellaneous Worksheet Formats

Many older formats supported only one worksheet:

• dBASE and Visual FoxPro (DBF)

DBF is really a typed table format: each column can only hold one data type and each record omits type information. The parser generates a header row and inserts records starting at the second row of the worksheet. The writer makes files compatible with Visual FoxPro extensions.

Multi-file extensions like external memos and tables are currently unsupported, limited by the general ability to read arbitrary files in the web browser. The reader understands DBF Level 7 extensions like DATETIME.

• Symbolic Link (SYLK)

There is no real documentation. All knowledge was gathered by saving files in various versions of Excel to deduce the meaning of fields. Notes:

Plain formulae are stored in the RC form.

Column widths are rounded to integral characters.

Lotus Formatted Text (PRN)

There is no real documentation, and in fact Excel treats PRN as an output-only file format. Nevertheless we can guess the column widths and reverse-engineer the original layout. Excel's 240 character width limitation is not enforced.

• Data Interchange Format (DIF)

There is no unified definition. Visicalc DIF differs from Lotus DIF, and both differ from Excel DIF. Where ambiguous, the parser/writer follows the expected behavior from Excel. In particular, Excel extends DIF in incompatible ways:

Since Excel automatically converts numbers-as-strings to numbers, numeric string constants are converted to formulae: `"0.3" -> "=""0.3""`

DIF technically expects numeric cells to hold the raw numeric data, but Excel permits formatted numbers (including dates)

DIF technically has no support for formulae, but Excel will automatically convert plain formulae. Array formulae are not preserved.

HTML

Excel HTML worksheets include special metadata encoded in styles. For example, `mso-number-format` is a localized string containing the number format. Despite the metadata the output is valid HTML, although it does accept bare `&` symbols.

The writer adds type metadata to the TD elements via the `t` tag. The parser looks for those tags and overrides the default interpretation. For example, text like `<td>12345</td>` will be parsed as numbers but `<td t="s">12345</td>` will be parsed as text.

• Rich Text Format (RTF)

Excel RTF worksheets are stored in clipboard when copying cells or ranges from a worksheet. The supported codes are a subset of the Word RTF support.

• Ethercalc Record Format (ETH)

Ethercalc is an open source web spreadsheet powered by a record format reminiscent of SYLK wrapped in a MIME multi-part message.

## Testing

### Node

(click to show)

`make test` will run the node-based tests. By default it runs tests on files in every supported format. To test a specific file type, set `FMTS` to the format you want to test. Feature-specific tests are available with `make test_misc`

``````\$ make test_misc   # run core tests
\$ make test        # run full tests
\$ make test_xls    # only use the XLS test files
\$ make test_xlsx   # only use the XLSX test files
\$ make test_xlsb   # only use the XLSB test files
\$ make test_xml    # only use the XML test files
\$ make test_ods    # only use the ODS test files
``````

To enable all errors, set the environment variable `WTF=1`:

``````\$ make test        # run full tests
\$ WTF=1 make test  # enable all error messages
``````

`flow` and `eslint` checks are available:

``````\$ make lint        # eslint checks
\$ make flow        # make lint + Flow checking
\$ make tslint      # check TS definitions
``````

### Browser

(click to show)

The core in-browser tests are available at `tests/index.html` within this repo. Start a local server and navigate to that directory to run the tests. `make ctestserv` will start a server on port 8000.

`make ctest` will generate the browser fixtures. To add more files, edit the `tests/fixtures.lst` file and add the paths.

To run the full in-browser tests, clone the repo for `oss.sheetjs.com` and replace the `xlsx.js` file (then open a browser window and go to `stress.html`):

``````\$ cp xlsx.js ../SheetJS.github.io
\$ cd ../SheetJS.github.io
\$ simplehttpserver # or "python -mSimpleHTTPServer" or "serve"
\$ open -a Chromium.app http://localhost:8000/stress.html
``````

### Tested Environments

(click to show)

• NodeJS `0.8`, `0.10`, `0.12`, `4.x`, `5.x`, `6.x`, `7.x`, `8.x`
• IE 6/7/8/9/10/11 (IE 6-9 require shims)
• Chrome 24+ (including Android 4.0+)
• Safari 6+ (iOS and Desktop)
• Edge 13+, FF 18+, and Opera 12+

Tests utilize the mocha testing framework.

The test suite also includes tests for various time zones. To change the timezone locally, set the TZ environment variable:

``````\$ env TZ="Asia/Kolkata" WTF=1 make test_misc
``````

### Test Files

Test files are housed in another repo.

Running `make init` will refresh the `test_files` submodule and get the files. Note that this requires `svn`, `git`, `hg` and other commands that may not be available. If `make init` fails, please download the latest version of the test files snapshot from the repo

Latest Snapshot (click to show)

(download and unzip to the `test_files` subdirectory)

## Contributing

Due to the precarious nature of the Open Specifications Promise, it is very important to ensure code is cleanroom. Contribution Notes

File organization (click to show)

At a high level, the final script is a concatenation of the individual files in the `bits` folder. Running `make` should reproduce the final output on all platforms. The README is similarly split into bits in the `docbits` folder.

Folders:

After cloning the repo, running `make help` will display a list of commands.

### OSX/Linux

(click to show)

The `xlsx.js` file is constructed from the files in the `bits` subdirectory. The build script (run `make`) will concatenate the individual bits to produce the script. Before submitting a contribution, ensure that running make will produce the `xlsx.js` file exactly. The simplest way to test is to add the script:

``````\$ git add xlsx.js
\$ make clean
\$ make
\$ git diff xlsx.js
``````

To produce the dist files, run `make dist`. The dist files are updated in each version release and should not be committed between versions.

### Windows

(click to show)

The included `make.cmd` script will build `xlsx.js` from the `bits` directory. Building is as simple as:

``````> make
``````

To prepare development environment:

``````> make init
``````

The full list of commands available in Windows are displayed in `make help`:

``````make init -- install deps and global modules
make lint -- run eslint linter
make test -- run mocha test suite
make misc -- run smaller test suite
make book -- rebuild README and summary
make help -- display this message
``````

As explained in Test Files, on Windows the release ZIP file must be downloaded and extracted. If Bash on Windows is available, it is possible to run the OSX/Linux workflow. The following steps prepares the environment:

``````# Install support programs for the build and test commands
sudo apt-get install make git subversion mercurial

# Install nodejs and NPM within the WSL
wget -qO- https://deb.nodesource.com/setup_8.x | sudo bash
sudo apt-get install nodejs

# Install dev dependencies
sudo npm install -g mocha voc blanket xlsjs
``````

### Tests

(click to show)

The `test_misc` target (`make test_misc` on Linux/OSX / `make misc` on Windows) runs the targeted feature tests. It should take 5-10 seconds to perform feature tests without testing against the entire test battery. New features should be accompanied with tests for the relevant file formats and features.

For tests involving the read side, an appropriate feature test would involve reading an existing file and checking the resulting workbook object. If a parameter is involved, files should be read with different values to verify that the feature is working as expected.

For tests involving a new write feature which can already be parsed, appropriate feature tests would involve writing a workbook with the feature and then opening and verifying that the feature is preserved.

For tests involving a new write feature without an existing read ability, please add a feature test to the kitchen sink `tests/write.js`.

## References

OSP-covered Specifications (click to show)

• `MS-CFB`: Compound File Binary File Format
• `MS-CTXLS`: Excel Custom Toolbar Binary File Format
• `MS-EXSPXML3`: Excel Calculation Version 2 Web Service XML Schema
• `MS-ODATA`: Open Data Protocol (OData)
• `MS-ODRAW`: Office Drawing Binary File Format
• `MS-ODRAWXML`: Office Drawing Extensions to Office Open XML Structure
• `MS-OE376`: Office Implementation Information for ECMA-376 Standards Support
• `MS-OFFCRYPTO`: Office Document Cryptography Structure
• `MS-OI29500`: Office Implementation Information for ISO/IEC 29500 Standards Support
• `MS-OLEDS`: Object Linking and Embedding (OLE) Data Structures
• `MS-OLEPS`: Object Linking and Embedding (OLE) Property Set Data Structures
• `MS-OODF3`: Office Implementation Information for ODF 1.2 Standards Support
• `MS-OSHARED`: Office Common Data Types and Objects Structures
• `MS-OVBA`: Office VBA File Format Structure
• `MS-XLDM`: Spreadsheet Data Model File Format
• `MS-XLS`: Excel Binary File Format (.xls) Structure Specification
• `MS-XLSB`: Excel (.xlsb) Binary File Format
• `MS-XLSX`: Excel (.xlsx) Extensions to the Office Open XML SpreadsheetML File Format
• `XLS`: Microsoft Office Excel 97-2007 Binary File Format Specification
• `RTF`: Rich Text Format
• ISO/IEC 29500:2012(E) "Information technology — Document description and processing languages — Office Open XML File Formats"
• Open Document Format for Office Applications Version 1.2 (29 September 2011)
• Worksheet File Format (From Lotus) December 1984

Author: SheetJS
Source Code: https://github.com/SheetJS/sheetjs

1650512040

## SheetJS Community Edition -- Spreadsheet Data Toolkit

SheetJS

The SheetJS Community Edition offers battle-tested open-source solutions for extracting useful data from almost any complex spreadsheet and generating new spreadsheets that will work with legacy and modern software alike.

SheetJS Pro offers solutions beyond data processing: Edit complex templates with ease; let out your inner Picasso with styling; make custom sheets with images/graphs/PivotTables; evaluate formula expressions and port calculations to web apps; automate common spreadsheet tasks, and much more!

## Getting Started

### Installation

#### Standalone Browser Scripts

Each standalone release script is available at https://cdn.sheetjs.com/.

The current version is `0.18.6` and can be referenced as follows:

``````<!-- use version 0.18.6 -->
<script lang="javascript" src="https://cdn.sheetjs.com/xlsx-0.18.6/package/dist/xlsx.full.min.js"></script>
``````

The `latest` tag references the latest version and updates with each release:

``````<!-- use the latest version -->
<script lang="javascript" src="https://cdn.sheetjs.com/xlsx-latest/package/dist/xlsx.full.min.js"></script>
``````

For production use, scripts should be downloaded and added to a public folder alongside other scripts.

Browser builds (click to show)

The complete single-file version is generated at `dist/xlsx.full.min.js`

`dist/xlsx.core.min.js` omits codepage library (no support for XLS encodings)

A slimmer build is generated at `dist/xlsx.mini.min.js`. Compared to full build:

• codepage library skipped (no support for XLS encodings)
• no support for XLSB / XLS / Lotus 1-2-3 / SpreadsheetML 2003 / Numbers
• node stream utils removed

These scripts are also available on the CDN:

``````<!-- use xlsx.mini.min.js from version 0.18.6 -->
<script lang="javascript" src="https://cdn.sheetjs.com/xlsx-0.18.6/package/dist/xlsx.mini.min.js"></script>
``````

Bower will pull the entire repo:

``````\$ bower install js-xlsx
``````

Bower will place the standalone scripts in `bower_components/js-xlsx/dist/`

Internet Explorer and ECMAScript 3 Compatibility (click to show)

For broad compatibility with JavaScript engines, the library is written using ECMAScript 3 language dialect as well as some ES5 features like `Array#forEach`. Older browsers require shims to provide missing functions.

To use the shim, add the shim before the script tag that loads `xlsx.js`:

``````<!-- add the shim first -->
<script type="text/javascript" src="shim.min.js"></script>
<!-- after the shim is referenced, add the library -->
<script type="text/javascript" src="xlsx.full.min.js"></script>
``````

Due to SSL certificate compatibility issues, it is highly recommended to save the Standalone and Shim scripts from https://cdn.sheetjs.com/ and add to a public directory in the site.

The script also includes `IE_LoadFile` and `IE_SaveFile` for loading and saving files in Internet Explorer versions 6-9. The `xlsx.extendscript.js` script bundles the shim in a format suitable for Photoshop and other Adobe products.

#### ECMAScript Modules

Browser ESM

The ECMAScript Module build is saved to `xlsx.mjs` and can be directly added to a page with a `script` tag using `type="module"`:

``````<script type="module">
import { read, writeFileXLSX } from "https://cdn.sheetjs.com/xlsx-0.18.6/package/xlsx.mjs";

/* load the codepage support library for extended support with older formats  */
import { set_cptable } from "https://cdn.sheetjs.com/xlsx-0.18.6/package/xlsx.mjs";
import * as cptable from 'https://cdn.sheetjs.com/xlsx-0.18.6/package/dist/cpexcel.full.mjs';
set_cptable(cptable);
</script>
``````

Frameworks (Angular, VueJS, React) and Bundlers (webpack, etc)

The NodeJS package is readily installed from the tarballs:

``````\$ npm  install --save https://cdn.sheetjs.com/xlsx-0.18.6/xlsx-0.18.6.tgz # npm
\$ pnpm install --save https://cdn.sheetjs.com/xlsx-0.18.6/xlsx-0.18.6.tgz # pnpm
\$ yarn add     --save https://cdn.sheetjs.com/xlsx-0.18.6/xlsx-0.18.6.tgz # yarn
``````

Once installed, the library can be imported under the name `xlsx`:

``````import { read, writeFileXLSX } from "xlsx";

/* load the codepage support library for extended support with older formats  */
import { set_cptable } from "xlsx";
import * as cptable from 'xlsx/dist/cpexcel.full.mjs';
set_cptable(cptable);
``````

#### Deno

`xlsx.mjs` can be imported in Deno:

``````// @deno-types="https://cdn.sheetjs.com/xlsx-0.18.6/package/types/index.d.ts"
import * as XLSX from 'https://cdn.sheetjs.com/xlsx-0.18.6/package/xlsx.mjs';

/* load the codepage support library for extended support with older formats  */
import * as cptable from 'https://cdn.sheetjs.com/xlsx-0.18.6/package/dist/cpexcel.full.mjs';
XLSX.set_cptable(cptable);
``````

#### NodeJS

Tarballs are available on https://cdn.sheetjs.com.

Each individual version can be referenced using a similar URL pattern. https://cdn.sheetjs.com/xlsx-0.18.6/xlsx-0.18.6.tgz is the URL for `0.18.6`

https://cdn.sheetjs.com/xlsx-latest/xlsx-latest.tgz is a link to the latest version and will refresh on each release.

Installation

Tarballs can be directly installed using a package manager:

``````\$ npm  install https://cdn.sheetjs.com/xlsx-0.18.6/xlsx-0.18.6.tgz # npm
\$ pnpm install https://cdn.sheetjs.com/xlsx-0.18.6/xlsx-0.18.6.tgz # pnpm
\$ yarn add     https://cdn.sheetjs.com/xlsx-0.18.6/xlsx-0.18.6.tgz # yarn
``````

For general stability, "vendoring" modules is the recommended approach:

Download the tarball (`xlsx-0.18.6.tgz`) for the desired version. The current version is available at https://cdn.sheetjs.com/xlsx-0.18.6/xlsx-0.18.6.tgz

Create a `vendor` subdirectory at the root of your project and move the tarball to that folder. Add it to your project repository.

Install the tarball using a package manager:

``````\$ npm  install --save file:vendor/xlsx-0.18.6.tgz # npm
\$ pnpm install --save file:vendor/xlsx-0.18.6.tgz # pnpm
\$ yarn add            file:vendor/xlsx-0.18.6.tgz # yarn
``````

The package will be installed and accessible as `xlsx`.

Usage

By default, the module supports `require` and it will automatically add support for streams and filesystem access:

``````var XLSX = require("xlsx");
``````

The module also ships with `xlsx.mjs` for use with `import`. The `mjs` version does not automatically load native node modules:

``````import * as XLSX from 'xlsx/xlsx.mjs';

/* load 'fs' for readFile and writeFile support */
import * as fs from 'fs';
XLSX.set_fs(fs);

/* load 'stream' for stream support */
import { Readable } from 'stream';

/* load the codepage support library for extended support with older formats  */
import * as cpexcel from 'xlsx/dist/cpexcel.full.mjs';
XLSX.set_cptable(cpexcel);
``````

#### Photoshop and InDesign

`dist/xlsx.extendscript.js` is an ExtendScript build for Photoshop and InDesign. https://cdn.sheetjs.com/xlsx-0.18.6/package/dist/xlsx.extendscript.js is the current version. After downloading the script, it can be directly referenced with a `#include` directive:

``````#include "xlsx.extendscript.js"
``````

### Usage

Most scenarios involving spreadsheets and data can be broken into 5 parts:

Acquire Data: Data may be stored anywhere: local or remote files, databases, HTML TABLE, or even generated programmatically in the web browser.

Extract Data: For spreadsheet files, this involves parsing raw bytes to read the cell data. For general JS data, this involves reshaping the data.

Process Data: From generating summary statistics to cleaning data records, this step is the heart of the problem.

Package Data: This can involve making a new spreadsheet or serializing with `JSON.stringify` or writing XML or simply flattening data for UI tools.

Release Data: Spreadsheet files can be uploaded to a server or written locally. Data can be presented to users in an HTML TABLE or data grid.

A common problem involves generating a valid spreadsheet export from data stored in an HTML table. In this example, an HTML TABLE on the page will be scraped, a row will be added to the bottom with the date of the report, and a new file will be generated and downloaded locally. `XLSX.writeFile` takes care of packaging the data and attempting a local download:

``````// Acquire Data (reference to the HTML table)
var table_elt = document.getElementById("my-table-id");

// Extract Data (create a workbook object from the table)
var workbook = XLSX.utils.table_to_book(table_elt);

// Process Data (add a new row)
var ws = workbook.Sheets["Sheet1"];
XLSX.utils.sheet_add_aoa(ws, [["Created "+new Date().toISOString()]], {origin:-1});

// Package and Release Data (`writeFile` tries to write and save an XLSB file)
XLSX.writeFile(workbook, "Report.xlsb");
``````

This library tries to simplify steps 2 and 4 with functions to extract useful data from spreadsheet files (`read` / `readFile`) and generate new spreadsheet files from data (`write` / `writeFile`). Additional utility functions like `table_to_book` work with other common data sources like HTML tables.

This documentation and various demo projects cover a number of common scenarios and approaches for steps 1 and 5.

Utility functions help with step 3.

"Acquiring and Extracting Data" describes solutions for common data import scenarios.

"Packaging and Releasing Data" describes solutions for common data export scenarios.

"Processing Data" describes solutions for common workbook processing and manipulation scenarios.

"Utility Functions" details utility functions for translating JSON Arrays and other common JS structures into worksheet objects.

### The Zen of SheetJS

Data processing should fit in any workflow

The library does not impose a separate lifecycle. It fits nicely in websites and apps built using any framework. The plain JS data objects play nice with Web Workers and future APIs.

JavaScript is a powerful language for data processing

The "Common Spreadsheet Format" is a simple object representation of the core concepts of a workbook. The various functions in the library provide low-level tools for working with the object.

For friendly JS processing, there are utility functions for converting parts of a worksheet to/from an Array of Arrays. The following example combines powerful JS Array methods with a network request library to download data, select the information we want and create a workbook file:

Get Data from a JSON Endpoint and Generate a Workbook (click to show)

The goal is to generate a XLSB workbook of US President names and birthdays.

Acquire Data

Raw Data

https://theunitedstates.io/congress-legislators/executive.json has the desired data. For example, John Adams:

``````{
"id": { /* (data omitted) */ },
"name": {
"first": "John",          // <-- first name
"last": "Adams"           // <-- last name
},
"bio": {
"birthday": "1735-10-19", // <-- birthday
"gender": "M"
},
"terms": [
{ "type": "viceprez", /* (other fields omitted) */ },
{ "type": "viceprez", /* (other fields omitted) */ },
{ "type": "prez", /* (other fields omitted) */ } // <-- look for "prez"
]
}
``````

Filtering for Presidents

The dataset includes Aaron Burr, a Vice President who was never President!

`Array#filter` creates a new array with the desired rows. A President served at least one term with `type` set to `"prez"`. To test if a particular row has at least one `"prez"` term, `Array#some` is another native JS function. The complete filter would be:

``````const prez = raw_data.filter(row => row.terms.some(term => term.type === "prez"));
``````

Lining up the data

For this example, the name will be the first name combined with the last name (`row.name.first + " " + row.name.last`) and the birthday will be the subfield `row.bio.birthday`. Using `Array#map`, the dataset can be massaged in one call:

``````const rows = prez.map(row => ({
name: row.name.first + " " + row.name.last,
birthday: row.bio.birthday
}));
``````

The result is an array of "simple" objects with no nesting:

``````[
{ name: "George Washington", birthday: "1732-02-22" },
{ name: "John Adams", birthday: "1735-10-19" },
// ... one row per President
]
``````

Extract Data

With the cleaned dataset, `XLSX.utils.json_to_sheet` generates a worksheet:

``````const worksheet = XLSX.utils.json_to_sheet(rows);
``````

`XLSX.utils.book_new` creates a new workbook and `XLSX.utils.book_append_sheet` appends a worksheet to the workbook. The new worksheet will be called "Dates":

``````const workbook = XLSX.utils.book_new();
XLSX.utils.book_append_sheet(workbook, worksheet, "Dates");
``````

Process Data

By default, `json_to_sheet` creates a worksheet with a header row. In this case, the headers come from the JS object keys: "name" and "birthday".

The headers are in cells A1 and B1. `XLSX.utils.sheet_add_aoa` can write text values to the existing worksheet starting at cell A1:

``````XLSX.utils.sheet_add_aoa(worksheet, [["Name", "Birthday"]], { origin: "A1" });
``````

Fixing Column Widths

Some of the names are longer than the default column width. Column widths are set by setting the `"!cols"` worksheet property.

The following line sets the width of column A to approximately 10 characters:

``````worksheet["!cols"] = [ { wch: 10 } ]; // set column A width to 10 characters
``````

One `Array#reduce` call over `rows` can calculate the maximum width:

``````const max_width = rows.reduce((w, r) => Math.max(w, r.name.length), 10);
worksheet["!cols"] = [ { wch: max_width } ];
``````

Note: If the starting point was a file or HTML table, `XLSX.utils.sheet_to_json` will generate an array of JS objects.

Package and Release Data

`XLSX.writeFile` creates a spreadsheet file and tries to write it to the system. In the browser, it will try to prompt the user to download the file. In NodeJS, it will write to the local directory.

``````XLSX.writeFile(workbook, "Presidents.xlsx");
``````

Complete Example

``````// Uncomment the next line for use in NodeJS:
// const XLSX = require("xlsx"), axios = require("axios");

(async() => {
/* fetch JSON data and parse */
const url = "https://theunitedstates.io/congress-legislators/executive.json";
const raw_data = (await axios(url, {responseType: "json"})).data;

/* filter for the Presidents */
const prez = raw_data.filter(row => row.terms.some(term => term.type === "prez"));

/* flatten objects */
const rows = prez.map(row => ({
name: row.name.first + " " + row.name.last,
birthday: row.bio.birthday
}));

/* generate worksheet and workbook */
const worksheet = XLSX.utils.json_to_sheet(rows);
const workbook = XLSX.utils.book_new();
XLSX.utils.book_append_sheet(workbook, worksheet, "Dates");

/* fix headers */
XLSX.utils.sheet_add_aoa(worksheet, [["Name", "Birthday"]], { origin: "A1" });

/* calculate column width */
const max_width = rows.reduce((w, r) => Math.max(w, r.name.length), 10);
worksheet["!cols"] = [ { wch: max_width } ];

/* create an XLSX file and try to save to Presidents.xlsx */
XLSX.writeFile(workbook, "Presidents.xlsx");
})();
``````

For use in the web browser, assuming the snippet is saved to `snippet.js`, script tags should be used to include the `axios` and `xlsx` standalone builds:

``````<script src="https://cdn.sheetjs.com/xlsx-latest/package/dist/xlsx.full.min.js"></script>
<script src="https://unpkg.com/axios/dist/axios.min.js"></script>
<script src="snippet.js"></script>
``````

File formats are implementation details

The parser covers a wide gamut of common spreadsheet file formats to ensure that "HTML-saved-as-XLS" files work as well as actual XLS or XLSX files.

The writer supports a number of common output formats for broad compatibility with the data ecosystem.

To the greatest extent possible, data processing code should not have to worry about the specific file formats involved.

### JS Ecosystem Demos

The `demos` directory includes sample projects for:

Frameworks and APIs

Bundlers and Tooling

Platforms and Integrations

Other examples are included in the showcase.

https://sheetjs.com/demos/modify.html shows a complete example of reading, modifying, and writing files.

https://github.com/SheetJS/sheetjs/blob/HEAD/bin/xlsx.njs is the command-line tool included with node installations, reading spreadsheet files and exporting the contents in various formats.

## Acquiring and Extracting Data

### Parsing Workbooks

API

Extract data from spreadsheet bytes

``````var workbook = XLSX.read(data, opts);
``````

The `read` method can extract data from spreadsheet bytes stored in a JS string, "binary string", NodeJS buffer or typed array (`Uint8Array` or `ArrayBuffer`).

Read spreadsheet bytes from a local file and extract data

``````var workbook = XLSX.readFile(filename, opts);
``````

The `readFile` method attempts to read a spreadsheet file at the supplied path. Browsers generally do not allow reading files in this way (it is deemed a security risk), and attempts to read files in this way will throw an error.

The second `opts` argument is optional. "Parsing Options" covers the supported properties and behaviors.

Examples

Here are a few common scenarios (click on each subtitle to see the code):

Local file in a NodeJS server (click to show)

`readFile` uses `fs.readFileSync` under the hood:

``````var XLSX = require("xlsx");

var workbook = XLSX.readFile("test.xlsx");
``````

For Node ESM, the `readFile` helper is not enabled. Instead, `fs.readFileSync` should be used to read the file data as a `Buffer` for use with `XLSX.read`:

``````import { readFileSync } from "fs";
import { read } from "xlsx/xlsx.mjs";

const buf = readFileSync("test.xlsx");
/* buf is a Buffer */
const workbook = read(buf);
``````

Local file in a Deno application (click to show)

`readFile` uses `Deno.readFileSync` under the hood:

``````// @deno-types="https://deno.land/x/sheetjs/types/index.d.ts"
import * as XLSX from 'https://deno.land/x/sheetjs/xlsx.mjs'

const workbook = XLSX.readFile("test.xlsx");
``````

Applications reading files must be invoked with the `--allow-read` flag. The `deno` demo has more examples

User-submitted file in a web page ("Drag-and-Drop") (click to show)

For modern websites targeting Chrome 76+, `File#arrayBuffer` is recommended:

``````// XLSX is a global from the standalone script

async function handleDropAsync(e) {
e.stopPropagation(); e.preventDefault();
const f = e.dataTransfer.files[0];
/* f is a File */
const data = await f.arrayBuffer();
/* data is an ArrayBuffer */
const workbook = XLSX.read(data);

/* DO SOMETHING WITH workbook HERE */
}
``````

For maximal compatibility, the `FileReader` API should be used:

``````function handleDrop(e) {
e.stopPropagation(); e.preventDefault();
var f = e.dataTransfer.files[0];
/* f is a File */
var data = e.target.result;
/* reader.readAsArrayBuffer(file) -> data will be an ArrayBuffer */
var workbook = XLSX.read(data);

/* DO SOMETHING WITH workbook HERE */
};
}
``````

https://oss.sheetjs.com/sheetjs/ demonstrates the FileReader technique.

User-submitted file with an HTML INPUT element (click to show)

Starting with an HTML INPUT element with `type="file"`:

``````<input type="file" id="input_dom_element">
``````

For modern websites targeting Chrome 76+, `Blob#arrayBuffer` is recommended:

``````// XLSX is a global from the standalone script

async function handleFileAsync(e) {
const file = e.target.files[0];
const data = await file.arrayBuffer();
/* data is an ArrayBuffer */
const workbook = XLSX.read(data);

/* DO SOMETHING WITH workbook HERE */
}
``````

For broader support (including IE10+), the `FileReader` approach is recommended:

``````function handleFile(e) {
var file = e.target.files[0];
var data = e.target.result;
/* reader.readAsArrayBuffer(file) -> data will be an ArrayBuffer */
var workbook = XLSX.read(e.target.result);

/* DO SOMETHING WITH workbook HERE */
};
}
``````

The `oldie` demo shows an IE-compatible fallback scenario.

Fetching a file in the web browser ("Ajax") (click to show)

For modern websites targeting Chrome 42+, `fetch` is recommended:

``````// XLSX is a global from the standalone script

(async() => {
const url = "http://oss.sheetjs.com/test_files/formula_stress_test.xlsx";
const data = await (await fetch(url)).arrayBuffer();
/* data is an ArrayBuffer */
const workbook = XLSX.read(data);

/* DO SOMETHING WITH workbook HERE */
})();
``````

For broader support, the `XMLHttpRequest` approach is recommended:

``````var url = "http://oss.sheetjs.com/test_files/formula_stress_test.xlsx";

/* set up async GET request */
var req = new XMLHttpRequest();
req.open("GET", url, true);
req.responseType = "arraybuffer";

req.onload = function(e) {
var workbook = XLSX.read(req.response);

/* DO SOMETHING WITH workbook HERE */
};

req.send();
``````

The `xhr` demo includes a longer discussion and more examples.

http://oss.sheetjs.com/sheetjs/ajax.html shows fallback approaches for IE6+.

Local file in a PhotoShop or InDesign plugin (click to show)

`readFile` wraps the `File` logic in Photoshop and other ExtendScript targets. The specified path should be an absolute path:

``````#include "xlsx.extendscript.js"

/* Read test.xlsx from the Documents folder */
var workbook = XLSX.readFile(Folder.myDocuments + "/test.xlsx");
``````

The `extendscript` demo includes a more complex example.

Local file in an Electron app (click to show)

`readFile` can be used in the renderer process:

``````/* From the renderer process */
var XLSX = require("xlsx");

var workbook = XLSX.readFile(path);
``````

Electron APIs have changed over time. The `electron` demo shows a complete example and details the required version-specific settings.

Local file in a mobile app with React Native (click to show)

The `react` demo includes a sample React Native app.

Since React Native does not provide a way to read files from the filesystem, a third-party library must be used. The following libraries have been tested:

The `base64` encoding returns strings compatible with the `base64` type:

``````import XLSX from "xlsx";
import { FileSystem } from "react-native-file-access";

const b64 = await FileSystem.readFile(path, "base64");
/* b64 is a base64 string */
const workbook = XLSX.read(b64, {type: "base64"});
``````

The `ascii` encoding returns binary strings compatible with the `binary` type:

``````import XLSX from "xlsx";
import { readFile } from "react-native-fs";

const bstr = await readFile(path, "ascii");
/* bstr is a binary string */
const workbook = XLSX.read(bstr, {type: "binary"});
``````

NodeJS Server File Uploads (click to show)

`read` can accept a NodeJS buffer. `readFile` can read files generated by a HTTP POST request body parser like `formidable`:

``````const XLSX = require("xlsx");
const http = require("http");
const formidable = require("formidable");

const server = http.createServer((req, res) => {
const form = new formidable.IncomingForm();
form.parse(req, (err, fields, files) => {
/* grab the first file */
const f = Object.entries(files)[0][1];
const path = f.filepath;
const workbook = XLSX.readFile(path);

/* DO SOMETHING WITH workbook HERE */
});
}).listen(process.env.PORT || 7262);
``````

The `server` demo has more advanced examples.

Download files in a NodeJS process (click to show)

Node 17.5 and 18.0 have native support for fetch:

``````const XLSX = require("xlsx");

const data = await (await fetch(url)).arrayBuffer();
/* data is an ArrayBuffer */
const workbook = XLSX.read(data);
``````

For broader compatibility, third-party modules are recommended.

`request` requires a `null` encoding to yield Buffers:

``````var XLSX = require("xlsx");
var request = require("request");

request({url: url, encoding: null}, function(err, resp, body) {
var workbook = XLSX.read(body);

/* DO SOMETHING WITH workbook HERE */
});
``````

`axios` works the same way in browser and in NodeJS:

``````const XLSX = require("xlsx");
const axios = require("axios");

(async() => {
const res = await axios.get(url, {responseType: "arraybuffer"});
/* res.data is a Buffer */
const workbook = XLSX.read(res.data);

/* DO SOMETHING WITH workbook HERE */
})();
``````

Download files in an Electron app (click to show)

The `net` module in the main process can make HTTP/HTTPS requests to external resources. Responses should be manually concatenated using `Buffer.concat`:

``````const XLSX = require("xlsx");
const { net } = require("electron");

const req = net.request(url);
req.on("response", (res) => {
const bufs = []; // this array will collect all of the buffers
res.on("data", (chunk) => { bufs.push(chunk); });
res.on("end", () => {
const workbook = XLSX.read(Buffer.concat(bufs));

/* DO SOMETHING WITH workbook HERE */
});
});
req.end();
``````

Readable Streams in NodeJS (click to show)

When dealing with Readable Streams, the easiest approach is to buffer the stream and process the whole thing at the end:

``````var fs = require("fs");
var XLSX = require("xlsx");

function process_RS(stream, cb) {
var buffers = [];
stream.on("data", function(data) { buffers.push(data); });
stream.on("end", function() {
var buffer = Buffer.concat(buffers);
var workbook = XLSX.read(buffer, {type:"buffer"});

/* DO SOMETHING WITH workbook IN THE CALLBACK */
cb(workbook);
});
}
``````

ReadableStream in the browser (click to show)

When dealing with `ReadableStream`, the easiest approach is to buffer the stream and process the whole thing at the end:

``````// XLSX is a global from the standalone script

async function process_RS(stream) {
/* collect data */
const buffers = [];
for(;;) {
if(res.value) buffers.push(res.value);
if(res.done) break;
}

/* concat */
const out = new Uint8Array(buffers.reduce((acc, v) => acc + v.length, 0));

let off = 0;
for(const u8 of arr) {
out.set(u8, off);
off += u8.length;
}

return out;
}

const data = await process_RS(stream);
/* data is Uint8Array */
const workbook = XLSX.read(data);
``````

More detailed examples are covered in the included demos

### Processing JSON and JS Data

JSON and JS data tend to represent single worksheets. This section will use a few utility functions to generate workbooks.

Create a new Workbook

``````var workbook = XLSX.utils.book_new();
``````

The `book_new` utility function creates an empty workbook with no worksheets.

Spreadsheet software generally require at least one worksheet and enforce the requirement in the user interface. This library enforces the requirement at write time, throwing errors if an empty workbook is passed to write functions.

API

Create a worksheet from an array of arrays of JS values

``````var worksheet = XLSX.utils.aoa_to_sheet(aoa, opts);
``````

The `aoa_to_sheet` utility function walks an "array of arrays" in row-major order, generating a worksheet object. The following snippet generates a sheet with cell `A1` set to the string `A1`, cell `B1` set to `B1`, etc:

``````var worksheet = XLSX.utils.aoa_to_sheet([
["A1", "B1", "C1"],
["A2", "B2", "C2"],
["A3", "B3", "C3"]
]);
``````

"Array of Arrays Input" describes the function and the optional `opts` argument in more detail.

Create a worksheet from an array of JS objects

``````var worksheet = XLSX.utils.json_to_sheet(jsa, opts);
``````

The `json_to_sheet` utility function walks an array of JS objects in order, generating a worksheet object. By default, it will generate a header row and one row per object in the array. The optional `opts` argument has settings to control the column order and header output.

"Array of Objects Input" describes the function and the optional `opts` argument in more detail.

Examples

"Zen of SheetJS" contains a detailed example "Get Data from a JSON Endpoint and Generate a Workbook"

`x-spreadsheet` is an interactive data grid for previewing and modifying structured data in the web browser. The `xspreadsheet` demo includes a sample script with the `xtos` function for converting from x-spreadsheet data object to a workbook. https://oss.sheetjs.com/sheetjs/x-spreadsheet is a live demo.

Records from a database query (SQL or no-SQL) (click to show)

The `database` demo includes examples of working with databases and query results.

Numerical Computations with TensorFlow.js (click to show)

`@tensorflow/tfjs` and other libraries expect data in simple arrays, well-suited for worksheets where each column is a data vector. That is the transpose of how most people use spreadsheets, where each row is a vector.

When recovering data from `tfjs`, the returned data points are stored in a typed array. An array of arrays can be constructed with loops. `Array#unshift` can prepend a title row before the conversion:

``````const XLSX = require("xlsx");
const tf = require('@tensorflow/tfjs');

/* suppose xs and ys are vectors (1D tensors) -> tfarr will be a typed array */
const tfdata = tf.stack([xs, ys]).transpose();
const shape = tfdata.shape;
const tfarr = tfdata.dataSync();

/* construct the array of arrays */
const aoa = [];
for(let j = 0; j < shape[0]; ++j) {
aoa[j] = [];
for(let i = 0; i < shape[1]; ++i) aoa[j][i] = tfarr[j * shape[1] + i];
}
/* add headers to the top */
aoa.unshift(["x", "y"]);

/* generate worksheet */
const worksheet = XLSX.utils.aoa_to_sheet(aoa);
``````

The `array` demo shows a complete example.

### Processing HTML Tables

API

Create a worksheet by scraping an HTML TABLE in the page

``````var worksheet = XLSX.utils.table_to_sheet(dom_element, opts);
``````

The `table_to_sheet` utility function takes a DOM TABLE element and iterates through the rows to generate a worksheet. The `opts` argument is optional. "HTML Table Input" describes the function in more detail.

Create a workbook by scraping an HTML TABLE in the page

``````var workbook = XLSX.utils.table_to_book(dom_element, opts);
``````

The `table_to_book` utility function follows the same logic as `table_to_sheet`. After generating a worksheet, it creates a blank workbook and appends the spreadsheet.

The options argument supports the same options as `table_to_sheet`, with the addition of a `sheet` property to control the worksheet name. If the property is missing or no options are specified, the default name `Sheet1` is used.

Examples

Here are a few common scenarios (click on each subtitle to see the code):

HTML TABLE element in a webpage (click to show)

``````<!-- include the standalone script and shim.  this uses the UNPKG CDN -->
<script src="https://cdn.sheetjs.com/xlsx-latest/package/dist/shim.min.js"></script>
<script src="https://cdn.sheetjs.com/xlsx-latest/package/dist/xlsx.full.min.js"></script>

<!-- example table with id attribute -->
<table id="tableau">
<tr><td>Sheet</td><td>JS</td></tr>
<tr><td>12345</td><td>67</td></tr>
</table>

<!-- this block should appear after the table HTML and the standalone script -->
<script type="text/javascript">
var workbook = XLSX.utils.table_to_book(document.getElementById("tableau"));

/* DO SOMETHING WITH workbook HERE */
</script>
``````

Multiple tables on a web page can be converted to individual worksheets:

``````/* create new workbook */
var workbook = XLSX.utils.book_new();

/* convert table "table1" to worksheet named "Sheet1" */
var sheet1 = XLSX.utils.table_to_sheet(document.getElementById("table1"));
XLSX.utils.book_append_sheet(workbook, sheet1, "Sheet1");

/* convert table "table2" to worksheet named "Sheet2" */
var sheet2 = XLSX.utils.table_to_sheet(document.getElementById("table2"));
XLSX.utils.book_append_sheet(workbook, sheet2, "Sheet2");

/* workbook now has 2 worksheets */
``````

Alternatively, the HTML code can be extracted and parsed:

``````var htmlstr = document.getElementById("tableau").outerHTML;
var workbook = XLSX.read(htmlstr, {type:"string"});
``````

Chrome/Chromium Extension (click to show)

The `chrome` demo shows a complete example and details the required permissions and other settings.

In an extension, it is recommended to generate the workbook in a content script and pass the object back to the extension:

``````/* in the worker script */
chrome.runtime.onMessage.addListener(function(msg, sender, cb) {
/* pass a message like { sheetjs: true } from the extension to scrape */
if(!msg || !msg.sheetjs) return;
/* create a new workbook */
var workbook = XLSX.utils.book_new();
/* loop through each table element */
var tables = document.getElementsByTagName("table")
for(var i = 0; i < tables.length; ++i) {
var worksheet = XLSX.utils.table_to_sheet(tables[i]);
XLSX.utils.book_append_sheet(workbook, worksheet, "Table" + i);
}
/* pass back to the extension */
return cb(workbook);
});
``````

Server-Side HTML Tables with Headless Chrome (click to show)

The `headless` demo includes a complete demo to convert HTML files to XLSB workbooks. The core idea is to add the script to the page, parse the table in the page context, generate a `base64` workbook and send it back for further processing:

``````const XLSX = require("xlsx");
const { readFileSync } = require("fs"), puppeteer = require("puppeteer");

const url = `https://sheetjs.com/demos/table`;

/* get the standalone build source (node_modules/xlsx/dist/xlsx.full.min.js) */
const lib = readFileSync(require.resolve("xlsx/dist/xlsx.full.min.js"), "utf8");

(async() => {
/* start browser and go to web page */
const browser = await puppeteer.launch();
const page = await browser.newPage();
await page.goto(url, {waitUntil: "networkidle2"});

/* inject library */

/* this function `s5s` will be called by the script below, receiving the Base64-encoded file */
await page.exposeFunction("s5s", async(b64) => {
const workbook = XLSX.read(b64, {type: "base64" });

/* DO SOMETHING WITH workbook HERE */
});

/* generate XLSB file in webpage context and send back result */
/* call table_to_book on first table */
var workbook = XLSX.utils.table_to_book(document.querySelector("TABLE"));

/* generate XLSX file */
var b64 = XLSX.write(workbook, {type: "base64", bookType: "xlsb"});

/* call "s5s" hook exposed from the node process */
window.s5s(b64);
`});

/* cleanup */
await browser.close();
})();
``````

Server-Side HTML Tables with Headless WebKit (click to show)

The `headless` demo includes a complete demo to convert HTML files to XLSB workbooks using PhantomJS. The core idea is to add the script to the page, parse the table in the page context, generate a `binary` workbook and send it back for further processing:

``````var XLSX = require('xlsx');
var page = require('webpage').create();

/* this code will be run in the page */
var code = [ "function(){",
/* call table_to_book on first table */
"var wb = XLSX.utils.table_to_book(document.body.getElementsByTagName('table')[0]);",

/* generate XLSB file and return binary string */
"return XLSX.write(wb, {type: 'binary', bookType: 'xlsb'});",
"}" ].join("");

page.open('https://sheetjs.com/demos/table', function() {
/* Load the browser script from the UNPKG CDN */
page.includeJs("https://cdn.sheetjs.com/xlsx-latest/package/dist/xlsx.full.min.js", function() {
/* The code will return an XLSB file encoded as binary string */
var bin = page.evaluateJavaScript(code);

var workbook = XLSX.read(bin, {type: "binary"});
/* DO SOMETHING WITH workbook HERE */

phantom.exit();
});
});
``````

NodeJS HTML Tables without a browser (click to show)

NodeJS does not include a DOM implementation and Puppeteer requires a hefty Chromium build. `jsdom` is a lightweight alternative:

``````const XLSX = require("xlsx");
const { readFileSync } = require("fs");
const { JSDOM } = require("jsdom");

/* obtain HTML string.  This example reads from test.html */
const html_str = fs.readFileSync("test.html", "utf8");
/* get first TABLE element */
const doc = new JSDOM(html_str).window.document.querySelector("table");
/* generate workbook */
const workbook = XLSX.utils.table_to_book(doc);
``````

## Processing Data

The "Common Spreadsheet Format" is a simple object representation of the core concepts of a workbook. The utility functions work with the object representation and are intended to handle common use cases.

### Modifying Workbook Structure

API

Append a Worksheet to a Workbook

``````XLSX.utils.book_append_sheet(workbook, worksheet, sheet_name);
``````

The `book_append_sheet` utility function appends a worksheet to the workbook. The third argument specifies the desired worksheet name. Multiple worksheets can be added to a workbook by calling the function multiple times. If the worksheet name is already used in the workbook, it will throw an error.

Append a Worksheet to a Workbook and find a unique name

``````var new_name = XLSX.utils.book_append_sheet(workbook, worksheet, name, true);
``````

If the fourth argument is `true`, the function will start with the specified worksheet name. If the sheet name exists in the workbook, a new worksheet name will be chosen by finding the name stem and incrementing the counter:

``````XLSX.utils.book_append_sheet(workbook, sheetA, "Sheet2", true); // Sheet2
XLSX.utils.book_append_sheet(workbook, sheetB, "Sheet2", true); // Sheet3
XLSX.utils.book_append_sheet(workbook, sheetC, "Sheet2", true); // Sheet4
XLSX.utils.book_append_sheet(workbook, sheetD, "Sheet2", true); // Sheet5
``````

List the Worksheet names in tab order

``````var wsnames = workbook.SheetNames;
``````

The `SheetNames` property of the workbook object is a list of the worksheet names in "tab order". API functions will look at this array.

Replace a Worksheet in place

``````workbook.Sheets[sheet_name] = new_worksheet;
``````

The `Sheets` property of the workbook object is an object whose keys are names and whose values are worksheet objects. By reassigning to a property of the `Sheets` object, the worksheet object can be changed without disrupting the rest of the worksheet structure.

Examples

Add a new worksheet to a workbook (click to show)

This example uses `XLSX.utils.aoa_to_sheet`.

``````var ws_name = "SheetJS";

/* Create worksheet */
var ws_data = [
[ "S", "h", "e", "e", "t", "J", "S" ],
[  1 ,  2 ,  3 ,  4 ,  5 ]
];
var ws = XLSX.utils.aoa_to_sheet(ws_data);

/* Add the worksheet to the workbook */
XLSX.utils.book_append_sheet(wb, ws, ws_name);
``````

### Modifying Cell Values

API

Modify a single cell value in a worksheet

``````XLSX.utils.sheet_add_aoa(worksheet, [[new_value]], { origin: address });
``````

Modify multiple cell values in a worksheet

``````XLSX.utils.sheet_add_aoa(worksheet, aoa, opts);
``````

The `sheet_add_aoa` utility function modifies cell values in a worksheet. The first argument is the worksheet object. The second argument is an array of arrays of values. The `origin` key of the third argument controls where cells will be written. The following snippet sets `B3=1` and `E5="abc"`:

``````XLSX.utils.sheet_add_aoa(worksheet, [
[1],                             // <-- Write 1 to cell B3
,                                // <-- Do nothing in row 4
[/*B5*/, /*C5*/, /*D5*/, "abc"]  // <-- Write "abc" to cell E5
], { origin: "B3" });
``````

"Array of Arrays Input" describes the function and the optional `opts` argument in more detail.

Examples

Appending rows to a worksheet (click to show)

The special origin value `-1` instructs `sheet_add_aoa` to start in column A of the row after the last row in the range, appending the data:

``````XLSX.utils.sheet_add_aoa(worksheet, [
["first row after data", 1],
["second row after data", 2]
], { origin: -1 });
``````

### Modifying Other Worksheet / Workbook / Cell Properties

The "Common Spreadsheet Format" section describes the object structures in greater detail.

## Packaging and Releasing Data

### Writing Workbooks

API

Generate spreadsheet bytes (file) from data

``````var data = XLSX.write(workbook, opts);
``````

The `write` method attempts to package data from the workbook into a file in memory. By default, XLSX files are generated, but that can be controlled with the `bookType` property of the `opts` argument. Based on the `type` option, the data can be stored as a "binary string", JS string, `Uint8Array` or Buffer.

The second `opts` argument is required. "Writing Options" covers the supported properties and behaviors.

Generate and attempt to save file

``````XLSX.writeFile(workbook, filename, opts);
``````

The `writeFile` method packages the data and attempts to save the new file. The export file format is determined by the extension of `filename` (`SheetJS.xlsx` signals XLSX export, `SheetJS.xlsb` signals XLSB export, etc).

The `writeFile` method uses platform-specific APIs to initiate the file save. In NodeJS, `fs.readFileSync` can create a file. In the web browser, a download is attempted using the HTML5 `download` attribute, with fallbacks for IE.

Generate and attempt to save an XLSX file

``````XLSX.writeFileXLSX(workbook, filename, opts);
``````

The `writeFile` method embeds a number of different export functions. This is great for developer experience but not amenable to tree shaking using the current developer tools. When only XLSX exports are needed, this method avoids referencing the other export functions.

The second `opts` argument is optional. "Writing Options" covers the supported properties and behaviors.

Examples

Local file in a NodeJS server (click to show)

`writeFile` uses `fs.writeFileSync` in server environments:

``````var XLSX = require("xlsx");

/* output format determined by filename */
XLSX.writeFile(workbook, "out.xlsb");
``````

For Node ESM, the `writeFile` helper is not enabled. Instead, `fs.writeFileSync` should be used to write the file data to a `Buffer` for use with `XLSX.write`:

``````import { writeFileSync } from "fs";
import { write } from "xlsx/xlsx.mjs";

const buf = write(workbook, {type: "buffer", bookType: "xlsb"});
/* buf is a Buffer */
const workbook = writeFileSync("out.xlsb", buf);
``````

Local file in a Deno application (click to show)

`writeFile` uses `Deno.writeFileSync` under the hood:

``````// @deno-types="https://deno.land/x/sheetjs/types/index.d.ts"
import * as XLSX from 'https://deno.land/x/sheetjs/xlsx.mjs'

XLSX.writeFile(workbook, "test.xlsx");
``````

Applications writing files must be invoked with the `--allow-write` flag. The `deno` demo has more examples

Local file in a PhotoShop or InDesign plugin (click to show)

`writeFile` wraps the `File` logic in Photoshop and other ExtendScript targets. The specified path should be an absolute path:

``````#include "xlsx.extendscript.js"

/* output format determined by filename */
XLSX.writeFile(workbook, "out.xlsx");
/* at this point, out.xlsx is a file that you can distribute */
``````

The `extendscript` demo includes a more complex example.

Download a file in the browser to the user machine (click to show)

`XLSX.writeFile` wraps a few techniques for triggering a file save:

• `URL` browser API creates an object URL for the file, which the library uses by creating a link and forcing a click. It is supported in modern browsers.
• `msSaveBlob` is an IE10+ API for triggering a file save.
• `IE_FileSave` uses VBScript and ActiveX to write a file in IE6+ for Windows XP and Windows 7. The shim must be included in the containing HTML page.

There is no standard way to determine if the actual file has been downloaded.

``````/* output format determined by filename */
XLSX.writeFile(workbook, "out.xlsb");
/* at this point, out.xlsb will have been downloaded */
``````

Download a file in legacy browsers (click to show)

`XLSX.writeFile` techniques work for most modern browsers as well as older IE. For much older browsers, there are workarounds implemented by wrapper libraries.

`FileSaver.js` implements `saveAs`. Note: `XLSX.writeFile` will automatically call `saveAs` if available.

``````/* bookType can be any supported output type */
var wopts = { bookType:"xlsx", bookSST:false, type:"array" };

var wbout = XLSX.write(workbook,wopts);

/* the saveAs call downloads a file on the local machine */
saveAs(new Blob([wbout],{type:"application/octet-stream"}), "test.xlsx");
``````

`Downloadify` uses a Flash SWF button to generate local files, suitable for environments where ActiveX is unavailable:

``````Downloadify.create(id,{
filename: "test.xlsx",
data: function() { return XLSX.write(wb, {bookType:"xlsx", type:"base64"}); },
append: false,
dataType: "base64"
});
``````

The `oldie` demo shows an IE-compatible fallback scenario.

Browser upload file (ajax) (click to show)

A complete example using XHR is included in the XHR demo, along with examples for fetch and wrapper libraries. This example assumes the server can handle Base64-encoded files (see the demo for a basic nodejs server):

``````/* in this example, send a base64 string to the server */
var wopts = { bookType:"xlsx", bookSST:false, type:"base64" };

var wbout = XLSX.write(workbook,wopts);

var req = new XMLHttpRequest();
var formdata = new FormData();
formdata.append("file", "test.xlsx"); // <-- server expects `file` to hold name
formdata.append("data", wbout); // <-- `data` holds the base64-encoded data
req.send(formdata);
``````

PhantomJS (Headless Webkit) File Generation (click to show)

The `headless` demo includes a complete demo to convert HTML files to XLSB workbooks using PhantomJS. PhantomJS `fs.write` supports writing files from the main process but has a different interface from the NodeJS `fs` module:

``````var XLSX = require('xlsx');
var fs = require('fs');

/* generate a binary string */
var bin = XLSX.write(workbook, { type:"binary", bookType: "xlsx" });
/* write to file */
fs.write("test.xlsx", bin, "wb");
``````

Note: The section "Processing HTML Tables" shows how to generate a workbook from HTML tables in a page in "Headless WebKit".

The included demos cover mobile apps and other special deployments.

### Streaming Write

The streaming write functions are available in the `XLSX.stream` object. They take the same arguments as the normal write functions but return a NodeJS Readable Stream.

• `XLSX.stream.to_csv` is the streaming version of `XLSX.utils.sheet_to_csv`.
• `XLSX.stream.to_html` is the streaming version of `XLSX.utils.sheet_to_html`.
• `XLSX.stream.to_json` is the streaming version of `XLSX.utils.sheet_to_json`.

nodejs convert to CSV and write file (click to show)

``````var output_file_name = "out.csv";
var stream = XLSX.stream.to_csv(worksheet);
stream.pipe(fs.createWriteStream(output_file_name));
``````

nodejs write JSON stream to screen (click to show)

``````/* to_json returns an object-mode stream */
var stream = XLSX.stream.to_json(worksheet, {raw:true});

/* the following stream converts JS objects to text via JSON.stringify */
var conv = new Transform({writableObjectMode:true});
conv._transform = function(obj, e, cb){ cb(null, JSON.stringify(obj) + "\n"); };

stream.pipe(conv); conv.pipe(process.stdout);
``````

Exporting NUMBERS files (click to show)

The NUMBERS writer requires a fairly large base. The supplementary `xlsx.zahl` scripts provide support. `xlsx.zahl.js` is designed for standalone and NodeJS use, while `xlsx.zahl.mjs` is suitable for ESM.

Browser

``````<meta charset="utf8">
<script src="xlsx.full.min.js"></script>
<script src="xlsx.zahl.js"></script>
<script>
var wb = XLSX.utils.book_new(); var ws = XLSX.utils.aoa_to_sheet([
["SheetJS", "<3","விரிதாள்"],
[72,,"Arbeitsblätter"],
[,62,"数据"],
[true,false,],
]); XLSX.utils.book_append_sheet(wb, ws, "Sheet1");
XLSX.writeFile(wb, "textport.numbers", {numbers: XLSX_ZAHL, compression: true});
</script>
``````

Node

``````var XLSX = require("./xlsx.flow");
var XLSX_ZAHL = require("./dist/xlsx.zahl");
var wb = XLSX.utils.book_new(); var ws = XLSX.utils.aoa_to_sheet([
["SheetJS", "<3","விரிதாள்"],
[72,,"Arbeitsblätter"],
[,62,"数据"],
[true,false,],
]); XLSX.utils.book_append_sheet(wb, ws, "Sheet1");
XLSX.writeFile(wb, "textport.numbers", {numbers: XLSX_ZAHL, compression: true});
``````

Deno

``````import * as XLSX from './xlsx.mjs';
import XLSX_ZAHL from './dist/xlsx.zahl.mjs';

var wb = XLSX.utils.book_new(); var ws = XLSX.utils.aoa_to_sheet([
["SheetJS", "<3","விரிதாள்"],
[72,,"Arbeitsblätter"],
[,62,"数据"],
[true,false,],
]); XLSX.utils.book_append_sheet(wb, ws, "Sheet1");
XLSX.writeFile(wb, "textports.numbers", {numbers: XLSX_ZAHL, compression: true});
``````

https://github.com/sheetjs/sheetaki pipes write streams to nodejs response.

### Generating JSON and JS Data

JSON and JS data tend to represent single worksheets. The utility functions in this section work with single worksheets.

The "Common Spreadsheet Format" section describes the object structure in more detail. `workbook.SheetNames` is an ordered list of the worksheet names. `workbook.Sheets` is an object whose keys are sheet names and whose values are worksheet objects.

The "first worksheet" is stored at `workbook.Sheets[workbook.SheetNames[0]]`.

API

Create an array of JS objects from a worksheet

``````var jsa = XLSX.utils.sheet_to_json(worksheet, opts);
``````

Create an array of arrays of JS values from a worksheet

``````var aoa = XLSX.utils.sheet_to_json(worksheet, {...opts, header: 1});
``````

The `sheet_to_json` utility function walks a workbook in row-major order, generating an array of objects. The second `opts` argument controls a number of export decisions including the type of values (JS values or formatted text). The "JSON" section describes the argument in more detail.

By default, `sheet_to_json` scans the first row and uses the values as headers. With the `header: 1` option, the function exports an array of arrays of values.

Examples

`x-spreadsheet` is an interactive data grid for previewing and modifying structured data in the web browser. The `xspreadsheet` demo includes a sample script with the `stox` function for converting from a workbook to x-spreadsheet data object. https://oss.sheetjs.com/sheetjs/x-spreadsheet is a live demo.

Previewing data in a React data grid (click to show)

`react-data-grid` is a data grid tailored for react. It expects two properties: `rows` of data objects and `columns` which describe the columns. For the purposes of massaging the data to fit the react data grid API it is easiest to start from an array of arrays.

This demo starts by fetching a remote file and using `XLSX.read` to extract:

``````import { useEffect, useState } from "react";
import DataGrid from "react-data-grid";
import { read, utils } from "xlsx";

const url = "https://oss.sheetjs.com/test_files/RkNumber.xls";

export default function App() {
const [columns, setColumns] = useState([]);
const [rows, setRows] = useState([]);
useEffect(() => {(async () => {
const wb = read(await (await fetch(url)).arrayBuffer(), { WTF: 1 });

/* use sheet_to_json with header: 1 to generate an array of arrays */
const data = utils.sheet_to_json(wb.Sheets[wb.SheetNames[0]], { header: 1 });

/* see react-data-grid docs to understand the shape of the expected data */
setColumns(data[0].map((r) => ({ key: r, name: r })));
setRows(data.slice(1).map((r) => r.reduce((acc, x, i) => {
acc[data[0][i]] = x;
return acc;
}, {})));
})(); });

return <DataGrid columns={columns} rows={rows} />;
}
``````

Previewing data in a VueJS data grid (click to show)

`vue3-table-lite` is a simple VueJS 3 data table. It is featured in the VueJS demo.

Populating a database (SQL or no-SQL) (click to show)

The `database` demo includes examples of working with databases and query results.

Numerical Computations with TensorFlow.js (click to show)

`@tensorflow/tfjs` and other libraries expect data in simple arrays, well-suited for worksheets where each column is a data vector. That is the transpose of how most people use spreadsheets, where each row is a vector.

A single `Array#map` can pull individual named rows from `sheet_to_json` export:

``````const XLSX = require("xlsx");
const tf = require('@tensorflow/tfjs');

const key = "age"; // this is the field we want to pull
const ages = XLSX.utils.sheet_to_json(worksheet).map(r => r[key]);
const tf_data = tf.tensor1d(ages);
``````

All fields can be processed at once using a transpose of the 2D tensor generated with the `sheet_to_json` export with `header: 1`. The first row, if it contains header labels, should be removed with a slice:

``````const XLSX = require("xlsx");
const tf = require('@tensorflow/tfjs');

/* array of arrays of the data starting on the second row */
const aoa = XLSX.utils.sheet_to_json(worksheet, {header: 1}).slice(1);
/* dataset in the "correct orientation" */
const tf_dataset = tf.tensor2d(aoa).transpose();
/* pull out each dataset with a slice */
const tf_field0 = tf_dataset.slice([0,0], [1,tensor.shape[1]]).flatten();
const tf_field1 = tf_dataset.slice([1,0], [1,tensor.shape[1]]).flatten();
``````

The `array` demo shows a complete example.

### Generating HTML Tables

API

Generate HTML Table from Worksheet

``````var html = XLSX.utils.sheet_to_html(worksheet);
``````

The `sheet_to_html` utility function generates HTML code based on the worksheet data. Each cell in the worksheet is mapped to a `<TD>` element. Merged cells in the worksheet are serialized by setting `colspan` and `rowspan` attributes.

Examples

The `sheet_to_html` utility function generates HTML code that can be added to any DOM element by setting the `innerHTML`:

``````var container = document.getElementById("tavolo");
container.innerHTML = XLSX.utils.sheet_to_html(worksheet);
``````

Combining with `fetch`, constructing a site from a workbook is straightforward:

Vanilla JS + HTML fetch workbook and generate table previews (click to show)

``````<body>
<style>TABLE { border-collapse: collapse; } TD { border: 1px solid; }</style>
<div id="tavolo"></div>
<script src="https://cdn.sheetjs.com/xlsx-latest/package/dist/xlsx.full.min.js"></script>
<script type="text/javascript">
(async() => {
/* fetch and parse workbook -- see the fetch example for details */
const workbook = XLSX.read(await (await fetch("sheetjs.xlsx")).arrayBuffer());

let output = [];
/* loop through the worksheet names in order */
workbook.SheetNames.forEach(name => {

/* generate HTML from the corresponding worksheets */
const worksheet = workbook.Sheets[name];
const html = XLSX.utils.sheet_to_html(worksheet);

/* add a header with the title name followed by the table */
output.push(`<H3>\${name}</H3>\${html}`);
});
/* write to the DOM at the end */
tavolo.innerHTML = output.join("\n");
})();
</script>
</body>
``````

React fetch workbook and generate HTML table previews (click to show)

It is generally recommended to use a React-friendly workflow, but it is possible to generate HTML and use it in React with `dangerouslySetInnerHTML`:

``````function Tabeller(props) {
/* the workbook object is the state */
const [workbook, setWorkbook] = React.useState(XLSX.utils.book_new());

/* fetch and update the workbook with an effect */
React.useEffect(() => { (async() => {
/* fetch and parse workbook -- see the fetch example for details */
const wb = XLSX.read(await (await fetch("sheetjs.xlsx")).arrayBuffer());
setWorkbook(wb);
})(); });

return workbook.SheetNames.map(name => (<>
<h3>name</h3>
<div dangerouslySetInnerHTML={{
/* this __html mantra is needed to set the inner HTML */
__html: XLSX.utils.sheet_to_html(workbook.Sheets[name])
}} />
</>));
}
``````

The `react` demo includes more React examples.

VueJS fetch workbook and generate HTML table previews (click to show)

It is generally recommended to use a VueJS-friendly workflow, but it is possible to generate HTML and use it in VueJS with the `v-html` directive:

``````import { read, utils } from 'xlsx';
import { reactive } from 'vue';

const S5SComponent = {
mounted() { (async() => {
/* fetch and parse workbook -- see the fetch example for details */
const workbook = read(await (await fetch("sheetjs.xlsx")).arrayBuffer());
/* loop through the worksheet names in order */
workbook.SheetNames.forEach(name => {
/* generate HTML from the corresponding worksheets */
const html = utils.sheet_to_html(workbook.Sheets[name]);
/* add to state */
this.wb.wb.push({ name, html });
});
})(); },
/* this state mantra is required for array updates to work */
setup() { return { wb: reactive({ wb: [] }) }; },
template: `
<div v-for="ws in wb.wb" :key="ws.name">
<h3>{{ ws.name }}</h3>
<div v-html="ws.html"></div>
</div>`
};
``````

The `vuejs` demo includes more React examples.

### Generating Single-Worksheet Snapshots

The `sheet_to_*` functions accept a worksheet object.

API

Generate a CSV from a single worksheet

``````var csv = XLSX.utils.sheet_to_csv(worksheet, opts);
``````

This snapshot is designed to replicate the "CSV UTF8 (`.csv`)" output type. "Delimiter-Separated Output" describes the function and the optional `opts` argument in more detail.

Generate "Text" from a single worksheet

``````var txt = XLSX.utils.sheet_to_txt(worksheet, opts);
``````

This snapshot is designed to replicate the "UTF16 Text (`.txt`)" output type. "Delimiter-Separated Output" describes the function and the optional `opts` argument in more detail.

Generate a list of formulae from a single worksheet

``````var fmla = XLSX.utils.sheet_to_formulae(worksheet);
``````

This snapshot generates an array of entries representing the embedded formulae. Array formulae are rendered in the form `range=formula` while plain cells are rendered in the form `cell=formula or value`. String literals are prefixed with an apostrophe `'`, consistent with Excel's formula bar display.

"Formulae Output" describes the function in more detail.

## Interface

`XLSX` is the exposed variable in the browser and the exported node variable

`XLSX.version` is the version of the library (added by the build script).

`XLSX.SSF` is an embedded version of the format library.

### Parsing functions

`XLSX.read(data, read_opts)` attempts to parse `data`.

`XLSX.readFile(filename, read_opts)` attempts to read `filename` and parse.

Parse options are described in the Parsing Options section.

### Writing functions

`XLSX.write(wb, write_opts)` attempts to write the workbook `wb`

`XLSX.writeFile(wb, filename, write_opts)` attempts to write `wb` to `filename`. In browser-based environments, it will attempt to force a client-side download.

`XLSX.writeFileAsync(filename, wb, o, cb)` attempts to write `wb` to `filename`. If `o` is omitted, the writer will use the third argument as the callback.

`XLSX.stream` contains a set of streaming write functions.

Write options are described in the Writing Options section.

### Utilities

Utilities are available in the `XLSX.utils` object and are described in the Utility Functions section:

Constructing:

• `book_new` creates an empty workbook
• `book_append_sheet` adds a worksheet to a workbook

Importing:

• `aoa_to_sheet` converts an array of arrays of JS data to a worksheet.
• `json_to_sheet` converts an array of JS objects to a worksheet.
• `table_to_sheet` converts a DOM TABLE element to a worksheet.
• `sheet_add_aoa` adds an array of arrays of JS data to an existing worksheet.
• `sheet_add_json` adds an array of JS objects to an existing worksheet.

Exporting:

• `sheet_to_json` converts a worksheet object to an array of JSON objects.
• `sheet_to_csv` generates delimiter-separated-values output.
• `sheet_to_txt` generates UTF16 formatted text.
• `sheet_to_html` generates HTML output.
• `sheet_to_formulae` generates a list of the formulae (with value fallbacks).

Cell and cell address manipulation:

• `format_cell` generates the text value for a cell (using number formats).
• `encode_row / decode_row` converts between 0-indexed rows and 1-indexed rows.
• `encode_col / decode_col` converts between 0-indexed columns and column names.
• `encode_cell / decode_cell` converts cell addresses.
• `encode_range / decode_range` converts cell ranges.

## Common Spreadsheet Format

SheetJS conforms to the Common Spreadsheet Format (CSF):

### General Structures

Cell address objects are stored as `{c:C, r:R}` where `C` and `R` are 0-indexed column and row numbers, respectively. For example, the cell address `B5` is represented by the object `{c:1, r:4}`.

Cell range objects are stored as `{s:S, e:E}` where `S` is the first cell and `E` is the last cell in the range. The ranges are inclusive. For example, the range `A3:B7` is represented by the object `{s:{c:0, r:2}, e:{c:1, r:6}}`. Utility functions perform a row-major order walk traversal of a sheet range:

``````for(var R = range.s.r; R <= range.e.r; ++R) {
for(var C = range.s.c; C <= range.e.c; ++C) {
var cell_address = {c:C, r:R};
/* if an A1-style address is needed, encode the address */
var cell_ref = XLSX.utils.encode_cell(cell_address);
}
}
``````

### Cell Object

Cell objects are plain JS objects with keys and values following the convention:

Built-in export utilities (such as the CSV exporter) will use the `w` text if it is available. To change a value, be sure to delete `cell.w` (or set it to `undefined`) before attempting to export. The utilities will regenerate the `w` text from the number format (`cell.z`) and the raw value if possible.

The actual array formula is stored in the `f` field of the first cell in the array range. Other cells in the range will omit the `f` field.

#### Data Types

The raw value is stored in the `v` value property, interpreted based on the `t` type property. This separation allows for representation of numbers as well as numeric text. There are 6 valid cell types:

Error values and interpretation (click to show)

Type `n` is the Number type. This includes all forms of data that Excel stores as numbers, such as dates/times and Boolean fields. Excel exclusively uses data that can be fit in an IEEE754 floating point number, just like JS Number, so the `v` field holds the raw number. The `w` field holds formatted text. Dates are stored as numbers by default and converted with `XLSX.SSF.parse_date_code`.

Type `d` is the Date type, generated only when the option `cellDates` is passed. Since JSON does not have a natural Date type, parsers are generally expected to store ISO 8601 Date strings like you would get from `date.toISOString()`. On the other hand, writers and exporters should be able to handle date strings and JS Date objects. Note that Excel disregards timezone modifiers and treats all dates in the local timezone. The library does not correct for this error.

Type `s` is the String type. Values are explicitly stored as text. Excel will interpret these cells as "number stored as text". Generated Excel files automatically suppress that class of error, but other formats may elicit errors.

Type `z` represents blank stub cells. They are generated in cases where cells have no assigned value but hold comments or other metadata. They are ignored by the core library data processing utility functions. By default these cells are not generated; the parser `sheetStubs` option must be set to `true`.

#### Dates

Excel Date Code details (click to show)

By default, Excel stores dates as numbers with a format code that specifies date processing. For example, the date `19-Feb-17` is stored as the number `42785` with a number format of `d-mmm-yy`. The `SSF` module understands number formats and performs the appropriate conversion.

XLSX also supports a special date type `d` where the data is an ISO 8601 date string. The formatter converts the date back to a number.

The default behavior for all parsers is to generate number cells. Setting `cellDates` to true will force the generators to store dates.

Time Zones and Dates (click to show)

Excel has no native concept of universal time. All times are specified in the local time zone. Excel limitations prevent specifying true absolute dates.

Following Excel, this library treats all dates as relative to local time zone.

Epochs: 1900 and 1904 (click to show)

Excel supports two epochs (January 1 1900 and January 1 1904). The workbook's epoch can be determined by examining the workbook's `wb.Workbook.WBProps.date1904` property:

``````!!(((wb.Workbook||{}).WBProps||{}).date1904)
``````

### Sheet Objects

Each key that does not start with `!` maps to a cell (using `A-1` notation)

`sheet[address]` returns the cell object for the specified address.

Special sheet keys (accessible as `sheet[key]`, each starting with `!`):

`sheet['!ref']`: A-1 based range representing the sheet range. Functions that work with sheets should use this parameter to determine the range. Cells that are assigned outside of the range are not processed. In particular, when writing a sheet by hand, cells outside of the range are not included

Functions that handle sheets should test for the presence of `!ref` field. If the `!ref` is omitted or is not a valid range, functions are free to treat the sheet as empty or attempt to guess the range. The standard utilities that ship with this library treat sheets as empty (for example, the CSV output is empty string).

When reading a worksheet with the `sheetRows` property set, the ref parameter will use the restricted range. The original range is set at `ws['!fullref']`

`sheet['!margins']`: Object representing the page margins. The default values follow Excel's "normal" preset. Excel also has a "wide" and a "narrow" preset but they are stored as raw measurements. The main properties are listed below:

Page margin details (click to show)

``````/* Set worksheet sheet to "normal" */
/* Set worksheet sheet to "wide" */
ws["!margins"]={left:1.0, right:1.0, top:1.0, bottom:1.0, header:0.5,footer:0.5}
/* Set worksheet sheet to "narrow" */
``````

#### Worksheet Object

In addition to the base sheet keys, worksheets also add:

`ws['!cols']`: array of column properties objects. Column widths are actually stored in files in a normalized manner, measured in terms of the "Maximum Digit Width" (the largest width of the rendered digits 0-9, in pixels). When parsed, the column objects store the pixel width in the `wpx` field, character width in the `wch` field, and the maximum digit width in the `MDW` field.

`ws['!rows']`: array of row properties objects as explained later in the docs. Each row object encodes properties including row height and visibility.

`ws['!merges']`: array of range objects corresponding to the merged cells in the worksheet. Plain text formats do not support merge cells. CSV export will write all cells in the merge range if they exist, so be sure that only the first cell (upper-left) in the range is set.

`ws['!outline']`: configure how outlines should behave. Options default to the default settings in Excel 2019:

• `ws['!protect']`: object of write sheet protection properties. The `password` key specifies the password for formats that support password-protected sheets (XLSX/XLSB/XLS). The writer uses the XOR obfuscation method. The following keys control the sheet protection -- set to `false` to enable a feature when sheet is locked or set to `true` to disable a feature:

Worksheet Protection Details (click to show)

• `ws['!autofilter']`: AutoFilter object following the schema:
``````type AutoFilter = {
ref:string; // A-1 based range representing the AutoFilter table range
}
``````

#### Chartsheet Object

Chartsheets are represented as standard sheets. They are distinguished with the `!type` property set to `"chart"`.

The underlying data and `!ref` refer to the cached data in the chartsheet. The first row of the chartsheet is the underlying header.

#### Macrosheet Object

Macrosheets are represented as standard sheets. They are distinguished with the `!type` property set to `"macro"`.

#### Dialogsheet Object

Dialogsheets are represented as standard sheets. They are distinguished with the `!type` property set to `"dialog"`.

### Workbook Object

`workbook.SheetNames` is an ordered list of the sheets in the workbook

`wb.Sheets[sheetname]` returns an object representing the worksheet.

`wb.Props` is an object storing the standard properties. `wb.Custprops` stores custom properties. Since the XLS standard properties deviate from the XLSX standard, XLS parsing stores core properties in both places.

`wb.Workbook` stores workbook-level attributes.

#### Workbook File Properties

The various file formats use different internal names for file properties. The workbook `Props` object normalizes the names:

File Properties (click to show)

For example, to set the workbook title property:

``````if(!wb.Props) wb.Props = {};
wb.Props.Title = "Insert Title Here";
``````

Custom properties are added in the workbook `Custprops` object:

``````if(!wb.Custprops) wb.Custprops = {};
wb.Custprops["Custom Property"] = "Custom Value";
``````

Writers will process the `Props` key of the options object:

``````/* force the Author to be "SheetJS" */
XLSX.write(wb, {Props:{Author:"SheetJS"}});
``````

### Workbook-Level Attributes

`wb.Workbook` stores workbook-level attributes.

#### Defined Names

`wb.Workbook.Names` is an array of defined name objects which have the keys:

Defined Name Properties (click to show)

Excel allows two sheet-scoped defined names to share the same name. However, a sheet-scoped name cannot collide with a workbook-scope name. Workbook writers may not enforce this constraint.

#### Workbook Views

`wb.Workbook.Views` is an array of workbook view objects which have the keys:

#### Miscellaneous Workbook Properties

`wb.Workbook.WBProps` holds other workbook properties:

### Document Features

Even for basic features like date storage, the official Excel formats store the same content in different ways. The parsers are expected to convert from the underlying file format representation to the Common Spreadsheet Format. Writers are expected to convert from CSF back to the underlying file format.

#### Formulae

The A1-style formula string is stored in the `f` field. Even though different file formats store the formulae in different ways, the formats are translated. Even though some formats store formulae with a leading equal sign, CSF formulae do not start with `=`.

Formulae File Format Support (click to show)

Since Excel prohibits named cells from colliding with names of A1 or RC style cell references, a (not-so-simple) regex conversion is possible. BIFF Parsed formulae and Lotus Parsed formulae have to be explicitly unwound. OpenFormula formulae can be converted with regular expressions.

Shared formulae are decompressed and each cell has the formula corresponding to its cell. Writers generally do not attempt to generate shared formulae.

Single-Cell Formulae

For simple formulae, the `f` key of the desired cell can be set to the actual formula text. This worksheet represents `A1=1`, `A2=2`, and `A3=A1+A2`:

``````var worksheet = {
"!ref": "A1:A3",
A1: { t:'n', v:1 },
A2: { t:'n', v:2 },
A3: { t:'n', v:3, f:'A1+A2' }
};
``````

Utilities like `aoa_to_sheet` will accept cell objects in lieu of values:

``````var worksheet = XLSX.utils.aoa_to_sheet([
[ 1 ], // A1
[ 2 ], // A2
[ {t: "n", v: 3, f: "A1+A2"} ] // A3
]);
``````

Cells with formula entries but no value will be serialized in a way that Excel and other spreadsheet tools will recognize. This library will not automatically compute formula results! For example, the following worksheet will include the `BESSELJ` function but the result will not be available in JavaScript:

``````var worksheet = XLSX.utils.aoa_to_sheet([
[ 3.14159, 2 ], // Row "1"
[ { t:'n', f:'BESSELJ(A1,B1)' } ] // Row "2" will be calculated on file open
}
``````

If the actual results are needed in JS, SheetJS Pro offers a formula calculator component for evaluating expressions, updating values and dependent cells, and refreshing entire workbooks.

Array Formulae

Assign an array formula

``````XLSX.utils.sheet_set_array_formula(worksheet, range, formula);
``````

Array formulae are stored in the top-left cell of the array block. All cells of an array formula have a `F` field corresponding to the range. A single-cell formula can be distinguished from a plain formula by the presence of `F` field.

For example, setting the cell `C1` to the array formula `{=SUM(A1:A3*B1:B3)}`:

``````// API function
XLSX.utils.sheet_set_array_formula(worksheet, "C1", "SUM(A1:A3*B1:B3)");

// ... OR raw operations
worksheet['C1'] = { t:'n', f: "SUM(A1:A3*B1:B3)", F:"C1:C1" };
``````

For a multi-cell array formula, every cell has the same array range but only the first cell specifies the formula. Consider `D1:D3=A1:A3*B1:B3`:

``````// API function
XLSX.utils.sheet_set_array_formula(worksheet, "D1:D3", "A1:A3*B1:B3");

// ... OR raw operations
worksheet['D1'] = { t:'n', F:"D1:D3", f:"A1:A3*B1:B3" };
worksheet['D2'] = { t:'n', F:"D1:D3" };
worksheet['D3'] = { t:'n', F:"D1:D3" };
``````

Utilities and writers are expected to check for the presence of a `F` field and ignore any possible formula element `f` in cells other than the starting cell. They are not expected to perform validation of the formulae!

Dynamic Array Formulae

Assign a dynamic array formula

``````XLSX.utils.sheet_set_array_formula(worksheet, range, formula, true);
``````

Released in 2020, Dynamic Array Formulae are supported in the XLSX/XLSM and XLSB file formats. They are represented like normal array formulae but have special cell metadata indicating that the formula should be allowed to adjust the range.

An array formula can be marked as dynamic by setting the cell's `D` property to true. The `F` range is expected but can be the set to the current cell:

``````// API function
XLSX.utils.sheet_set_array_formula(worksheet, "C1", "_xlfn.UNIQUE(A1:A3)", 1);

// ... OR raw operations
worksheet['C1'] = { t: "s", f: "_xlfn.UNIQUE(A1:A3)", F:"C1", D: 1 }; // dynamic
``````

Localization with Function Names

SheetJS operates at the file level. Excel stores formula expressions using the English (United States) function names. For non-English users, Excel uses a localized set of function names.

For example, when the computer language and region is set to French (France), Excel interprets `=SOMME(A1:C3)` as if `SOMME` is the `SUM` function. However, in the actual file, Excel stores `SUM(A1:C3)`.

Prefixed "Future Functions"

Functions introduced in newer versions of Excel are prefixed with `_xlfn.` when stored in files. When writing formula expressions using these functions, the prefix is required for maximal compatibility:

``````// Broadest compatibility
XLSX.utils.sheet_set_array_formula(worksheet, "C1", "_xlfn.UNIQUE(A1:A3)", 1);

// Can cause errors in spreadsheet software
XLSX.utils.sheet_set_array_formula(worksheet, "C1", "UNIQUE(A1:A3)", 1);
``````

When reading a file, the `xlfn` option preserves the prefixes.

Functions requiring `_xlfn.` prefix (click to show)

This list is growing with each Excel release.

``````ACOT
ACOTH
AGGREGATE
ARABIC
BASE
BETA.DIST
BETA.INV
BINOM.DIST
BINOM.DIST.RANGE
BINOM.INV
BITAND
BITLSHIFT
BITOR
BITRSHIFT
BITXOR
BYCOL
BYROW
CEILING.MATH
CEILING.PRECISE
CHISQ.DIST
CHISQ.DIST.RT
CHISQ.INV
CHISQ.INV.RT
CHISQ.TEST
COMBINA
CONFIDENCE.NORM
CONFIDENCE.T
COT
COTH
COVARIANCE.P
COVARIANCE.S
CSC
CSCH
DAYS
DECIMAL
ERF.PRECISE
ERFC.PRECISE
EXPON.DIST
F.DIST
F.DIST.RT
F.INV
F.INV.RT
F.TEST
FIELDVALUE
FILTERXML
FLOOR.MATH
FLOOR.PRECISE
FORMULATEXT
GAMMA
GAMMA.DIST
GAMMA.INV
GAMMALN.PRECISE
GAUSS
HYPGEOM.DIST
IFNA
IMCOSH
IMCOT
IMCSC
IMCSCH
IMSEC
IMSECH
IMSINH
IMTAN
ISFORMULA
ISOMITTED
ISOWEEKNUM
LAMBDA
LET
LOGNORM.DIST
LOGNORM.INV
MAKEARRAY
MAP
MODE.MULT
MODE.SNGL
MUNIT
NEGBINOM.DIST
NORM.DIST
NORM.INV
NORM.S.DIST
NORM.S.INV
NUMBERVALUE
PDURATION
PERCENTILE.EXC
PERCENTILE.INC
PERCENTRANK.EXC
PERCENTRANK.INC
PERMUTATIONA
PHI
POISSON.DIST
QUARTILE.EXC
QUARTILE.INC
QUERYSTRING
RANDARRAY
RANK.AVG
RANK.EQ
REDUCE
RRI
SCAN
SEC
SECH
SEQUENCE
SHEET
SHEETS
SKEW.P
SORTBY
STDEV.P
STDEV.S
T.DIST
T.DIST.2T
T.DIST.RT
T.INV
T.INV.2T
T.TEST
UNICHAR
UNICODE
UNIQUE
VAR.P
VAR.S
WEBSERVICE
WEIBULL.DIST
XLOOKUP
XOR
Z.TEST
``````

#### Row and Column Properties

Format Support (click to show)

Row Properties: XLSX/M, XLSB, BIFF8 XLS, XLML, SYLK, DOM, ODS

Column Properties: XLSX/M, XLSB, BIFF8 XLS, XLML, SYLK, DOM

Row and Column properties are not extracted by default when reading from a file and are not persisted by default when writing to a file. The option `cellStyles: true` must be passed to the relevant read or write function.

Column Properties

The `!cols` array in each worksheet, if present, is a collection of `ColInfo` objects which have the following properties:

``````type ColInfo = {
/* visibility */
hidden?: boolean; // if true, the column is hidden

/* column width is specified in one of the following ways: */
wpx?:    number;  // width in screen pixels
width?:  number;  // width in Excel's "Max Digit Width", width*256 is integral
wch?:    number;  // width in characters

/* other fields for preserving features from files */
level?:  number;  // 0-indexed outline / group level
MDW?:    number;  // Excel's "Max Digit Width" unit, always integral
};
``````

Row Properties

The `!rows` array in each worksheet, if present, is a collection of `RowInfo` objects which have the following properties:

``````type RowInfo = {
/* visibility */
hidden?: boolean; // if true, the row is hidden

/* row height is specified in one of the following ways: */
hpx?:    number;  // height in screen pixels
hpt?:    number;  // height in points

level?:  number;  // 0-indexed outline / group level
};
``````

Outline / Group Levels Convention

The Excel UI displays the base outline level as `1` and the max level as `8`. Following JS conventions, SheetJS uses 0-indexed outline levels wherein the base outline level is `0` and the max level is `7`.

Why are there three width types? (click to show)

There are three different width types corresponding to the three different ways spreadsheets store column widths:

SYLK and other plain text formats use raw character count. Contemporaneous tools like Visicalc and Multiplan were character based. Since the characters had the same width, it sufficed to store a count. This tradition was continued into the BIFF formats.

SpreadsheetML (2003) tried to align with HTML by standardizing on screen pixel count throughout the file. Column widths, row heights, and other measures use pixels. When the pixel and character counts do not align, Excel rounds values.

XLSX internally stores column widths in a nebulous "Max Digit Width" form. The Max Digit Width is the width of the largest digit when rendered (generally the "0" character is the widest). The internal width must be an integer multiple of the the width divided by 256. ECMA-376 describes a formula for converting between pixels and the internal width. This represents a hybrid approach.

Read functions attempt to populate all three properties. Write functions will try to cycle specified values to the desired type. In order to avoid potential conflicts, manipulation should delete the other properties first. For example, when changing the pixel width, delete the `wch` and `width` properties.

Implementation details (click to show)

Row Heights

Excel internally stores row heights in points. The default resolution is 72 DPI or 96 PPI, so the pixel and point size should agree. For different resolutions they may not agree, so the library separates the concepts.

Even though all of the information is made available, writers are expected to follow the priority order:

1. use `hpx` pixel height if available
2. use `hpt` point height if available

Column Widths

Given the constraints, it is possible to determine the MDW without actually inspecting the font! The parsers guess the pixel width by converting from width to pixels and back, repeating for all possible MDW and selecting the MDW that minimizes the error. XLML actually stores the pixel width, so the guess works in the opposite direction.

Even though all of the information is made available, writers are expected to follow the priority order:

1. use `width` field if available
2. use `wpx` pixel width if available
3. use `wch` character count if available

#### Number Formats

The `cell.w` formatted text for each cell is produced from `cell.v` and `cell.z` format. If the format is not specified, the Excel `General` format is used. The format can either be specified as a string or as an index into the format table. Parsers are expected to populate `workbook.SSF` with the number format table. Writers are expected to serialize the table.

Custom tools should ensure that the local table has each used format string somewhere in the table. Excel convention mandates that the custom formats start at index 164. The following example creates a custom format from scratch:

New worksheet with custom format (click to show)

``````var wb = {
SheetNames: ["Sheet1"],
Sheets: {
Sheet1: {
"!ref":"A1:C1",
A1: { t:"n", v:10000 },                    // <-- General format
B1: { t:"n", v:10000, z: "0%" },           // <-- Builtin format
C1: { t:"n", v:10000, z: "\"T\"\ #0.00" }  // <-- Custom format
}
}
}
``````

The rules are slightly different from how Excel displays custom number formats. In particular, literal characters must be wrapped in double quotes or preceded by a backslash. For more info, see the Excel documentation article `Create or delete a custom number format` or ECMA-376 18.8.31 (Number Formats)

Default Number Formats (click to show)

The default formats are listed in ECMA-376 18.8.30:

Format 14 (`m/d/yy`) is localized by Excel: even though the file specifies that number format, it will be drawn differently based on system settings. It makes sense when the producer and consumer of files are in the same locale, but that is not always the case over the Internet. To get around this ambiguity, parse functions accept the `dateNF` option to override the interpretation of that specific format string.

Format Support (click to show)

Cell Hyperlinks: XLSX/M, XLSB, BIFF8 XLS, XLML, ODS

Tooltips: XLSX/M, XLSB, BIFF8 XLS, XLML

Hyperlinks are stored in the `l` key of cell objects. The `Target` field of the hyperlink object is the target of the link, including the URI fragment. Tooltips are stored in the `Tooltip` field and are displayed when you move your mouse over the text.

For example, the following snippet creates a link from cell `A3` to https://sheetjs.com with the tip `"Find us @ SheetJS.com!"`:

``````ws['A1'].l = { Target:"https://sheetjs.com", Tooltip:"Find us @ SheetJS.com!" };
``````

Note that Excel does not automatically style hyperlinks -- they will generally be displayed as normal text.

HTTP / HTTPS links can be used directly:

``````ws['A2'].l = { Target:"https://docs.sheetjs.com/#hyperlinks" };
ws['A3'].l = { Target:"http://localhost:7262/yes_localhost_works" };
``````

Excel also supports `mailto` email links with subject line:

``````ws['A4'].l = { Target:"mailto:ignored@dev.null" };
ws['A5'].l = { Target:"mailto:ignored@dev.null?subject=Test Subject" };
``````

Links to absolute paths should use the `file://` URI scheme:

``````ws['B1'].l = { Target:"file:///SheetJS/t.xlsx" }; /* Link to /SheetJS/t.xlsx */
ws['B2'].l = { Target:"file:///c:/SheetJS.xlsx" }; /* Link to c:\SheetJS.xlsx */
``````

Links to relative paths can be specified without a scheme:

``````ws['B3'].l = { Target:"SheetJS.xlsb" }; /* Link to SheetJS.xlsb */
ws['B4'].l = { Target:"../SheetJS.xlsm" }; /* Link to ../SheetJS.xlsm */
``````

Relative Paths have undefined behavior in the SpreadsheetML 2003 format. Excel 2019 will treat a `..\` parent mark as two levels up.

Links where the target is a cell or range or defined name in the same workbook ("Internal Links") are marked with a leading hash character:

``````ws['C1'].l = { Target:"#E2" }; /* Link to cell E2 */
ws['C2'].l = { Target:"#Sheet2!E2" }; /* Link to cell E2 in sheet Sheet2 */
ws['C3'].l = { Target:"#SomeDefinedName" }; /* Link to Defined Name */
``````

Cell comments are objects stored in the `c` array of cell objects. The actual contents of the comment are split into blocks based on the comment author. The `a` field of each comment object is the author of the comment and the `t` field is the plain text representation.

For example, the following snippet appends a cell comment into cell `A1`:

``````if(!ws.A1.c) ws.A1.c = [];
ws.A1.c.push({a:"SheetJS", t:"I'm a little comment, short and stout!"});
``````

Note: XLSB enforces a 54 character limit on the Author name. Names longer than 54 characters may cause issues with other formats.

To mark a comment as normally hidden, set the `hidden` property:

``````if(!ws.A1.c) ws.A1.c = [];
ws.A1.c.push({a:"SheetJS", t:"This comment is visible"});

if(!ws.A2.c) ws.A2.c = [];
ws.A2.c.hidden = true;
ws.A2.c.push({a:"SheetJS", t:"This comment will be hidden"});
``````

Introduced in Excel 365, threaded comments are plain text comment snippets with author metadata and parent references. They are supported in XLSX and XLSB.

To mark a comment as threaded, each comment part must have a true `T` property:

``````if(!ws.A1.c) ws.A1.c = [];
ws.A1.c.push({a:"SheetJS", t:"This is not threaded"});

if(!ws.A2.c) ws.A2.c = [];
ws.A2.c.hidden = true;
ws.A2.c.push({a:"SheetJS", t:"This is threaded", T: true});
ws.A2.c.push({a:"JSSheet", t:"This is also threaded", T: true});
``````

There is no Active Directory or Office 365 metadata associated with authors in a thread.

#### Sheet Visibility

Excel enables hiding sheets in the lower tab bar. The sheet data is stored in the file but the UI does not readily make it available. Standard hidden sheets are revealed in the "Unhide" menu. Excel also has "very hidden" sheets which cannot be revealed in the menu. It is only accessible in the VB Editor!

The visibility setting is stored in the `Hidden` property of sheet props array.

More details (click to show)

``````> wb.Workbook.Sheets.map(function(x) { return [x.name, x.Hidden] })
[ [ 'Visible', 0 ], [ 'Hidden', 1 ], [ 'VeryHidden', 2 ] ]
``````

Non-Excel formats do not support the Very Hidden state. The best way to test if a sheet is visible is to check if the `Hidden` property is logical truth:

``````> wb.Workbook.Sheets.map(function(x) { return [x.name, !x.Hidden] })
[ [ 'Visible', true ], [ 'Hidden', false ], [ 'VeryHidden', false ] ]
``````

#### VBA and Macros

VBA Macros are stored in a special data blob that is exposed in the `vbaraw` property of the workbook object when the `bookVBA` option is `true`. They are supported in `XLSM`, `XLSB`, and `BIFF8 XLS` formats. The supported format writers automatically insert the data blobs if it is present in the workbook and associate with the worksheet names.

Custom Code Names (click to show)

The workbook code name is stored in `wb.Workbook.WBProps.CodeName`. By default, Excel will write `ThisWorkbook` or a translated phrase like `DieseArbeitsmappe`. Worksheet and Chartsheet code names are in the worksheet properties object at `wb.Workbook.Sheets[i].CodeName`. Macrosheets and Dialogsheets are ignored.

The readers and writers preserve the code names, but they have to be manually set when adding a VBA blob to a different workbook.

Macrosheets (click to show)

Older versions of Excel also supported a non-VBA "macrosheet" sheet type that stored automation commands. These are exposed in objects with the `!type` property set to `"macro"`.

Detecting macros in workbooks (click to show)

The `vbaraw` field will only be set if macros are present, so testing is simple:

``````function wb_has_macro(wb/*:workbook*/)/*:boolean*/ {
if(!!wb.vbaraw) return true;
const sheets = wb.SheetNames.map((n) => wb.Sheets[n]);
return sheets.some((ws) => !!ws && ws['!type']=='macro');
}
``````

## Parsing Options

The exported `read` and `readFile` functions accept an options argument:

• Even if `cellNF` is false, formatted text will be generated and saved to `.w`
• In some cases, sheets may be parsed even if `bookSheets` is false.
• Excel aggressively tries to interpret values from CSV and other plain text. This leads to surprising behavior! The `raw` option suppresses value parsing.
• `bookSheets` and `bookProps` combine to give both sets of information
• `Deps` will be an empty object if `bookDeps` is false
• `bookFiles` behavior depends on file type:
• `keys` array (paths in the ZIP) for ZIP-based formats
• `files` hash (mapping paths to objects representing the files) for ZIP
• `cfb` object for formats using CFB containers
• `sheetRows-1` rows will be generated when looking at the JSON object output (since the header row is counted as a row when parsing the data)
• By default all worksheets are parsed. `sheets` restricts based on input type:
• number: zero-based index of worksheet to parse (`0` is first worksheet)
• string: name of worksheet to parse (case insensitive)
• array of numbers and strings to select multiple worksheets.
• `bookVBA` merely exposes the raw VBA CFB object. It does not parse the data. XLSM and XLSB store the VBA CFB object in `xl/vbaProject.bin`. BIFF8 XLS mixes the VBA entries alongside the core Workbook entry, so the library generates a new XLSB-compatible blob from the XLS CFB container.
• `codepage` is applied to BIFF2 - BIFF5 files without `CodePage` records and to CSV files without BOM in `type:"binary"`. BIFF8 XLS always defaults to 1200.
• `PRN` affects parsing of text files without a common delimiter character.
• Currently only XOR encryption is supported. Unsupported error will be thrown for files employing other encryption methods.
• Newer Excel functions are serialized with the `_xlfn.` prefix, hidden from the user. SheetJS will strip `_xlfn.` normally. The `xlfn` option preserves them.
• WTF is mainly for development. By default, the parser will suppress read errors on single worksheets, allowing you to read from the worksheets that do parse properly. Setting `WTF:true` forces those errors to be thrown.

### Input Type

Strings can be interpreted in multiple ways. The `type` parameter for `read` tells the library how to parse the data argument:

### Guessing File Type

Implementation Details (click to show)

Excel and other spreadsheet tools read the first few bytes and apply other heuristics to determine a file type. This enables file type punning: renaming files with the `.xls` extension will tell your computer to use Excel to open the file but Excel will know how to handle it. This library applies similar logic:

DBF files are detected based on the first byte as well as the third and fourth bytes (corresponding to month and day of the file date)

Works for Windows files are detected based on the BOF record with type `0xFF`

Plain text format guessing follows the priority order:

• HTML tags include: `html`, `table`, `head`, `meta`, `script`, `style`, `div`

Why are random text files valid? (click to show)

Excel is extremely aggressive in reading files. Adding an XLS extension to any display text file (where the only characters are ANSI display chars) tricks Excel into thinking that the file is potentially a CSV or TSV file, even if it is only one column! This library attempts to replicate that behavior.

The best approach is to validate the desired worksheet and ensure it has the expected number of rows or columns. Extracting the range is extremely simple:

``````var range = XLSX.utils.decode_range(worksheet['!ref']);
var ncols = range.e.c - range.s.c + 1, nrows = range.e.r - range.s.r + 1;
``````

## Writing Options

The exported `write` and `writeFile` functions accept an options argument:

• `bookSST` is slower and more memory intensive, but has better compatibility with older versions of iOS Numbers
• The raw data is the only thing guaranteed to be saved. Features not described in this README may not be serialized.
• `cellDates` only applies to XLSX output and is not guaranteed to work with third-party readers. Excel itself does not usually write cells with type `d` so non-Excel tools may ignore the data or error in the presence of dates.
• `Props` is an object mirroring the workbook `Props` field. See the table from the Workbook File Properties section.
• if specified, the string from `themeXLSX` will be saved as the primary theme for XLSX/XLSB/XLSM files (to `xl/theme/theme1.xml` in the ZIP)
• Due to a bug in the program, some features like "Text to Columns" will crash Excel on worksheets where error conditions are ignored. The writer will mark files to ignore the error by default. Set `ignoreEC` to `false` to suppress.
• Due to the size of the data, the NUMBERS data is not included by default. The included `xlsx.zahl.js` and `xlsx.zahl.mjs` scripts include the data.

### Supported Output Formats

For broad compatibility with third-party tools, this library supports many output formats. The specific file type is controlled with `bookType` option:

• `compression` only applies to formats with ZIP containers.
• Formats that only support a single sheet require a `sheet` option specifying the worksheet. If the string is empty, the first worksheet is used.
• `writeFile` will automatically guess the output file format based on the file extension if `bookType` is not specified. It will choose the first format in the aforementioned table that matches the extension.

### Output Type

The `type` argument for `write` mirrors the `type` argument for `read`:

• For compatibility with Excel, `csv` output will always include the UTF-8 byte order mark.

## Utility Functions

The `sheet_to_*` functions accept a worksheet and an optional options object.

The `*_to_sheet` functions accept a data object and an optional options object.

The examples are based on the following worksheet:

``````XXX| A | B | C | D | E | F | G |
---+---+---+---+---+---+---+---+
1 | S | h | e | e | t | J | S |
2 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
3 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
``````

### Array of Arrays Input

`XLSX.utils.aoa_to_sheet` takes an array of arrays of JS values and returns a worksheet resembling the input data. Numbers, Booleans and Strings are stored as the corresponding styles. Dates are stored as date or numbers. Array holes and explicit `undefined` values are skipped. `null` values may be stubbed. All other values are stored as strings. The function takes an options argument:

Examples (click to show)

To generate the example sheet:

``````var ws = XLSX.utils.aoa_to_sheet([
"SheetJS".split(""),
[1,2,3,4,5,6,7],
[2,3,4,5,6,7,8]
]);
``````

`XLSX.utils.sheet_add_aoa` takes an array of arrays of JS values and updates an existing worksheet object. It follows the same process as `aoa_to_sheet` and accepts an options argument:

`origin` is expected to be one of:

Examples (click to show)

Consider the worksheet:

``````XXX| A | B | C | D | E | F | G |
---+---+---+---+---+---+---+---+
1 | S | h | e | e | t | J | S |
2 | 1 | 2 |   |   | 5 | 6 | 7 |
3 | 2 | 3 |   |   | 6 | 7 | 8 |
4 | 3 | 4 |   |   | 7 | 8 | 9 |
5 | 4 | 5 | 6 | 7 | 8 | 9 | 0 |
``````

This worksheet can be built up in the order `A1:G1, A2:B4, E2:G4, A5:G5`:

``````/* Initial row */
var ws = XLSX.utils.aoa_to_sheet([ "SheetJS".split("") ]);

/* Write data starting at A2 */
XLSX.utils.sheet_add_aoa(ws, [[1,2], [2,3], [3,4]], {origin: "A2"});

/* Write data starting at E2 */
XLSX.utils.sheet_add_aoa(ws, [[5,6,7], [6,7,8], [7,8,9]], {origin:{r:1, c:4}});

/* Append row */
XLSX.utils.sheet_add_aoa(ws, [[4,5,6,7,8,9,0]], {origin: -1});
``````

### Array of Objects Input

`XLSX.utils.json_to_sheet` takes an array of objects and returns a worksheet with automatically-generated "headers" based on the keys of the objects. The default column order is determined by the first appearance of the field using `Object.keys`. The function accepts an options argument:

• All fields from each row will be written. If `header` is an array and it does not contain a particular field, the key will be appended to the array.
• Cell types are deduced from the type of each value. For example, a `Date` object will generate a Date cell, while a string will generate a Text cell.
• Null values will be skipped by default. If `nullError` is true, an error cell corresponding to `#NULL!` will be written to the worksheet.

Examples (click to show)

The original sheet cannot be reproduced using plain objects since JS object keys must be unique. After replacing the second `e` and `S` with `e_1` and `S_1`:

``````var ws = XLSX.utils.json_to_sheet([
{ S:1, h:2, e:3, e_1:4, t:5, J:6, S_1:7 },
{ S:2, h:3, e:4, e_1:5, t:6, J:7, S_1:8 }
``````

Alternatively, the header row can be skipped:

``````var ws = XLSX.utils.json_to_sheet([
{ A:"S", B:"h", C:"e", D:"e", E:"t", F:"J", G:"S" },
{ A: 1,  B: 2,  C: 3,  D: 4,  E: 5,  F: 6,  G: 7  },
{ A: 2,  B: 3,  C: 4,  D: 5,  E: 6,  F: 7,  G: 8  }
``````

`XLSX.utils.sheet_add_json` takes an array of objects and updates an existing worksheet object. It follows the same process as `json_to_sheet` and accepts an options argument:

`origin` is expected to be one of:

Examples (click to show)

Consider the worksheet:

``````XXX| A | B | C | D | E | F | G |
---+---+---+---+---+---+---+---+
1 | S | h | e | e | t | J | S |
2 | 1 | 2 |   |   | 5 | 6 | 7 |
3 | 2 | 3 |   |   | 6 | 7 | 8 |
4 | 3 | 4 |   |   | 7 | 8 | 9 |
5 | 4 | 5 | 6 | 7 | 8 | 9 | 0 |
``````

This worksheet can be built up in the order `A1:G1, A2:B4, E2:G4, A5:G5`:

``````/* Initial row */
var ws = XLSX.utils.json_to_sheet([
{ A: "S", B: "h", C: "e", D: "e", E: "t", F: "J", G: "S" }
], {header: ["A", "B", "C", "D", "E", "F", "G"], skipHeader: true});

/* Write data starting at A2 */
{ A: 1, B: 2 }, { A: 2, B: 3 }, { A: 3, B: 4 }
], {skipHeader: true, origin: "A2"});

/* Write data starting at E2 */
{ A: 5, B: 6, C: 7 }, { A: 6, B: 7, C: 8 }, { A: 7, B: 8, C: 9 }
], {skipHeader: true, origin: { r: 1, c: 4 }, header: [ "A", "B", "C" ]});

/* Append row */
{ A: 4, B: 5, C: 6, D: 7, E: 8, F: 9, G: 0 }
], {header: ["A", "B", "C", "D", "E", "F", "G"], skipHeader: true, origin: -1});
``````

### HTML Table Input

`XLSX.utils.table_to_sheet` takes a table DOM element and returns a worksheet resembling the input table. Numbers are parsed. All other data will be stored as strings.

`XLSX.utils.table_to_book` produces a minimal workbook based on the worksheet.

Both functions accept options arguments:

Examples (click to show)

To generate the example sheet, start with the HTML table:

``````<table id="sheetjs">
<tr><td>S</td><td>h</td><td>e</td><td>e</td><td>t</td><td>J</td><td>S</td></tr>
<tr><td>1</td><td>2</td><td>3</td><td>4</td><td>5</td><td>6</td><td>7</td></tr>
<tr><td>2</td><td>3</td><td>4</td><td>5</td><td>6</td><td>7</td><td>8</td></tr>
</table>
``````

To process the table:

``````var tbl = document.getElementById('sheetjs');
var wb = XLSX.utils.table_to_book(tbl);
``````

Note: `XLSX.read` can handle HTML represented as strings.

`XLSX.utils.sheet_add_dom` takes a table DOM element and updates an existing worksheet object. It follows the same process as `table_to_sheet` and accepts an options argument:

`origin` is expected to be one of:

Examples (click to show)

A small helper function can create gap rows between tables:

``````function create_gap_rows(ws, nrows) {
var ref = XLSX.utils.decode_range(ws["!ref"]);       // get original range
ref.e.r += nrows;                                    // add to ending row
ws["!ref"] = XLSX.utils.encode_range(ref);           // reassign row
}

/* first table */
var ws = XLSX.utils.table_to_sheet(document.getElementById('table1'));
create_gap_rows(ws, 1); // one row gap after first table

/* second table */
XLSX.utils.sheet_add_dom(ws, document.getElementById('table2'), {origin: -1});
create_gap_rows(ws, 3); // three rows gap after second table

/* third table */
XLSX.utils.sheet_add_dom(ws, document.getElementById('table3'), {origin: -1});
``````

### Formulae Output

`XLSX.utils.sheet_to_formulae` generates an array of commands that represent how a person would enter data into an application. Each entry is of the form `A1-cell-address=formula-or-value`. String literals are prefixed with a `'` in accordance with Excel.

Examples (click to show)

For the example sheet:

``````> var o = XLSX.utils.sheet_to_formulae(ws);
> [o[0], o[5], o[10], o[15], o[20]];
[ 'A1=\'S', 'F1=\'J', 'D2=4', 'B3=3', 'G3=8' ]
``````

### Delimiter-Separated Output

As an alternative to the `writeFile` CSV type, `XLSX.utils.sheet_to_csv` also produces CSV output. The function takes an options argument:

• `strip` will remove trailing commas from each line under default `FS/RS`
• `blankrows` must be set to `false` to skip blank lines.
• Fields containing the record or field separator will automatically be wrapped in double quotes; `forceQuotes` forces all cells to be wrapped in quotes.
• `XLSX.write` with `csv` type will always prepend the UTF-8 byte-order mark for Excel compatibility. `sheet_to_csv` returns a JS string and omits the mark. Using `XLSX.write` with type `string` will also skip the mark.

Examples (click to show)

For the example sheet:

``````> console.log(XLSX.utils.sheet_to_csv(ws));
S,h,e,e,t,J,S
1,2,3,4,5,6,7
2,3,4,5,6,7,8
> console.log(XLSX.utils.sheet_to_csv(ws, {FS:"\t"}));
S    h    e    e    t    J    S
1    2    3    4    5    6    7
2    3    4    5    6    7    8
> console.log(XLSX.utils.sheet_to_csv(ws,{FS:":",RS:"|"}));
S:h:e:e:t:J:S|1:2:3:4:5:6:7|2:3:4:5:6:7:8|
``````

#### UTF-16 Unicode Text

The `txt` output type uses the tab character as the field separator. If the `codepage` library is available (included in full distribution but not core), the output will be encoded in `CP1200` and the BOM will be prepended.

`XLSX.utils.sheet_to_txt` takes the same arguments as `sheet_to_csv`.

### HTML Output

As an alternative to the `writeFile` HTML type, `XLSX.utils.sheet_to_html` also produces HTML output. The function takes an options argument:

Examples (click to show)

For the example sheet:

``````> console.log(XLSX.utils.sheet_to_html(ws));
// ...
``````

### JSON

`XLSX.utils.sheet_to_json` generates different types of JS objects. The function takes an options argument:

• `raw` only affects cells which have a format code (`.z`) field or a formatted text (`.w`) field.
• If `header` is specified, the first row is considered a data row; if `header` is not specified, the first row is the header row and not considered data.
• When `header` is not specified, the conversion will automatically disambiguate header entries by affixing `_` and a count starting at `1`. For example, if three columns have header `foo` the output fields are `foo`, `foo_1`, `foo_2`
• `null` values are returned when `raw` is true but are skipped when false.
• If `defval` is not specified, null and undefined values are skipped normally. If specified, all null and undefined points will be filled with `defval`
• When `header` is `1`, the default is to generate blank rows. `blankrows` must be set to `false` to skip blank rows.
• When `header` is not `1`, the default is to skip blank rows. `blankrows` must be true to generate blank rows

`range` is expected to be one of:

`header` is expected to be one of:

• If header is not `1`, the row object will contain the non-enumerable property `__rowNum__` that represents the row of the sheet corresponding to the entry.
• If header is an array, the keys will not be disambiguated. This can lead to unexpected results if the array values are not unique!

Examples (click to show)

For the example sheet:

``````> XLSX.utils.sheet_to_json(ws);
[ { S: 1, h: 2, e: 3, e_1: 4, t: 5, J: 6, S_1: 7 },
{ S: 2, h: 3, e: 4, e_1: 5, t: 6, J: 7, S_1: 8 } ]

[ { A: 'S', B: 'h', C: 'e', D: 'e', E: 't', F: 'J', G: 'S' },
{ A: '1', B: '2', C: '3', D: '4', E: '5', F: '6', G: '7' },
{ A: '2', B: '3', C: '4', D: '5', E: '6', F: '7', G: '8' } ]

[ { '6': 'J', '9': 'S', A: 'S', E: 'h', I: 'e', O: 'e', U: 't' },
{ '6': '6', '9': '7', A: '1', E: '2', I: '3', O: '4', U: '5' },
{ '6': '7', '9': '8', A: '2', E: '3', I: '4', O: '5', U: '6' } ]

[ [ 'S', 'h', 'e', 'e', 't', 'J', 'S' ],
[ '1', '2', '3', '4', '5', '6', '7' ],
[ '2', '3', '4', '5', '6', '7', '8' ] ]
``````

Example showing the effect of `raw`:

``````> ws['A2'].w = "3";                          // set A2 formatted string value

> XLSX.utils.sheet_to_json(ws, {header:1, raw:false});
[ [ 'S', 'h', 'e', 'e', 't', 'J', 'S' ],
[ '3', '2', '3', '4', '5', '6', '7' ],     // <-- A2 uses the formatted string
[ '2', '3', '4', '5', '6', '7', '8' ] ]

[ [ 'S', 'h', 'e', 'e', 't', 'J', 'S' ],
[ 1, 2, 3, 4, 5, 6, 7 ],                   // <-- A2 uses the raw value
[ 2, 3, 4, 5, 6, 7, 8 ] ]
``````

## File Formats

Despite the library name `xlsx`, it supports numerous spreadsheet file formats:

Features not supported by a given file format will not be written. Formats with range limits will be silently truncated:

Excel 2003 SpreadsheetML range limits are governed by the version of Excel and are not enforced by the writer.

File Format Details (click to show)

• Excel 2007+ XML (XLSX/XLSM)

XLSX and XLSM files are ZIP containers containing a series of XML files in accordance with the Open Packaging Conventions (OPC). The XLSM format, almost identical to XLSX, is used for files containing macros.

The format is standardized in ECMA-376 and later in ISO/IEC 29500. Excel does not follow the specification, and there are additional documents discussing how Excel deviates from the specification.

• Excel 2.0-95 (BIFF2/BIFF3/BIFF4/BIFF5)

BIFF 2/3 XLS are single-sheet streams of binary records. Excel 4 introduced the concept of a workbook (`XLW` files) but also had single-sheet `XLS` format. The structure is largely similar to the Lotus 1-2-3 file formats. BIFF5/8/12 extended the format in various ways but largely stuck to the same record format.

There is no official specification for any of these formats. Excel 95 can write files in these formats, so record lengths and fields were determined by writing in all of the supported formats and comparing files. Excel 2016 can generate BIFF5 files, enabling a full suite of file tests starting from XLSX or BIFF2.

• Excel 97-2004 Binary (BIFF8)

BIFF8 exclusively uses the Compound File Binary container format, splitting some content into streams within the file. At its core, it still uses an extended version of the binary record format from older versions of BIFF.

The `MS-XLS` specification covers the basics of the file format, and other specifications expand on serialization of features like properties.

• Excel 2003-2004 (SpreadsheetML)

Predating XLSX, SpreadsheetML files are simple XML files. There is no official and comprehensive specification, although MS has released documentation on the format. Since Excel 2016 can generate SpreadsheetML files, mapping features is pretty straightforward.

• Excel 2007+ Binary (XLSB, BIFF12)

Introduced in parallel with XLSX, the XLSB format combines the BIFF architecture with the content separation and ZIP container of XLSX. For the most part nodes in an XLSX sub-file can be mapped to XLSB records in a corresponding sub-file.

The `MS-XLSB` specification covers the basics of the file format, and other specifications expand on serialization of features like properties.

• Delimiter-Separated Values (CSV/TXT)

Excel CSV deviates from RFC4180 in a number of important ways. The generated CSV files should generally work in Excel although they may not work in RFC4180 compatible readers. The parser should generally understand Excel CSV. The writer proactively generates cells for formulae if values are unavailable.

Excel TXT uses tab as the delimiter and code page 1200.

Like in Excel, files starting with `0x49 0x44 ("ID")` are treated as Symbolic Link files. Unlike Excel, if the file does not have a valid SYLK header, it will be proactively reinterpreted as CSV. There are some files with semicolon delimiter that align with a valid SYLK file. For the broadest compatibility, all cells with the value of `ID` are automatically wrapped in double-quotes.

Miscellaneous Workbook Formats

Support for other formats is generally far behind XLS/XLSB/XLSX support, due in part to a lack of publicly available documentation. Test files were produced in the respective apps and compared to their XLS exports to determine structure. The main focus is data extraction.

• Lotus 1-2-3 (WKS/WK1/WK2/WK3/WK4/123)

The Lotus formats consist of binary records similar to the BIFF structure. Lotus did release a specification decades ago covering the original WK1 format. Other features were deduced by producing files and comparing to Excel support.

Generated WK1 worksheets are compatible with Lotus 1-2-3 R2 and Excel 5.0.

Generated WK3 workbooks are compatible with Lotus 1-2-3 R9 and Excel 5.0.

• Quattro Pro (WQ1/WQ2/WB1/WB2/WB3/QPW)

The Quattro Pro formats use binary records in the same way as BIFF and Lotus. Some of the newer formats (namely WB3 and QPW) use a CFB enclosure just like BIFF8 XLS.

• Works for DOS / Windows Spreadsheet (WKS/XLR)

All versions of Works were limited to a single worksheet.

Works for DOS 1.x - 3.x and Works for Windows 2.x extends the Lotus WKS format with additional record types.

Works for Windows 3.x - 5.x uses the same format and WKS extension. The BOF record has type `FF`

Works for Windows 6.x - 9.x use the XLR format. XLR is nearly identical to BIFF8 XLS: it uses the CFB container with a Workbook stream. Works 9 saves the exact Workbook stream for the XLR and the 97-2003 XLS export. Works 6 XLS includes two empty worksheets but the main worksheet has an identical encoding. XLR also includes a `WksSSWorkBook` stream similar to Lotus FM3/FMT files.

• Numbers 3.0+ / iWork 2013+ Spreadsheet (NUMBERS)

iWork 2013 (Numbers 3.0 / Pages 5.0 / Keynote 6.0) switched from a proprietary XML-based format to the current file format based on the iWork Archive (IWA). This format has been used up through the current release (Numbers 11.2).

The parser focuses on extracting raw data from tables. Numbers technically supports multiple tables in a logical worksheet, including custom titles. This parser will generate one worksheet per Numbers table.

The writer currently exports a small range from the first worksheet.

• OpenDocument Spreadsheet (ODS/FODS)

ODS is an XML-in-ZIP format akin to XLSX while FODS is an XML format akin to SpreadsheetML. Both are detailed in the OASIS standard, but tools like LO/OO add undocumented extensions. The parsers and writers do not implement the full standard, instead focusing on parts necessary to extract and store raw data.

• Uniform Office Spreadsheet (UOS1/2)

UOS is a very similar format, and it comes in 2 varieties corresponding to ODS and FODS respectively. For the most part, the difference between the formats is in the names of tags and attributes.

Miscellaneous Worksheet Formats

Many older formats supported only one worksheet:

• dBASE and Visual FoxPro (DBF)

DBF is really a typed table format: each column can only hold one data type and each record omits type information. The parser generates a header row and inserts records starting at the second row of the worksheet. The writer makes files compatible with Visual FoxPro extensions.

Multi-file extensions like external memos and tables are currently unsupported, limited by the general ability to read arbitrary files in the web browser. The reader understands DBF Level 7 extensions like DATETIME.

• Symbolic Link (SYLK)

There is no real documentation. All knowledge was gathered by saving files in various versions of Excel to deduce the meaning of fields. Notes:

Plain formulae are stored in the RC form.

Column widths are rounded to integral characters.

Lotus Formatted Text (PRN)

There is no real documentation, and in fact Excel treats PRN as an output-only file format. Nevertheless we can guess the column widths and reverse-engineer the original layout. Excel's 240 character width limitation is not enforced.

• Data Interchange Format (DIF)

There is no unified definition. Visicalc DIF differs from Lotus DIF, and both differ from Excel DIF. Where ambiguous, the parser/writer follows the expected behavior from Excel. In particular, Excel extends DIF in incompatible ways:

Since Excel automatically converts numbers-as-strings to numbers, numeric string constants are converted to formulae: `"0.3" -> "=""0.3""`

DIF technically expects numeric cells to hold the raw numeric data, but Excel permits formatted numbers (including dates)

DIF technically has no support for formulae, but Excel will automatically convert plain formulae. Array formulae are not preserved.

HTML

Excel HTML worksheets include special metadata encoded in styles. For example, `mso-number-format` is a localized string containing the number format. Despite the metadata the output is valid HTML, although it does accept bare `&` symbols.

The writer adds type metadata to the TD elements via the `t` tag. The parser looks for those tags and overrides the default interpretation. For example, text like `<td>12345</td>` will be parsed as numbers but `<td t="s">12345</td>` will be parsed as text.

• Rich Text Format (RTF)

Excel RTF worksheets are stored in clipboard when copying cells or ranges from a worksheet. The supported codes are a subset of the Word RTF support.

• Ethercalc Record Format (ETH)

Ethercalc is an open source web spreadsheet powered by a record format reminiscent of SYLK wrapped in a MIME multi-part message.

## Testing

### Node

(click to show)

`make test` will run the node-based tests. By default it runs tests on files in every supported format. To test a specific file type, set `FMTS` to the format you want to test. Feature-specific tests are available with `make test_misc`

``````\$ make test_misc   # run core tests
\$ make test        # run full tests
\$ make test_xls    # only use the XLS test files
\$ make test_xlsx   # only use the XLSX test files
\$ make test_xlsb   # only use the XLSB test files
\$ make test_xml    # only use the XML test files
\$ make test_ods    # only use the ODS test files
``````

To enable all errors, set the environment variable `WTF=1`:

``````\$ make test        # run full tests
\$ WTF=1 make test  # enable all error messages
``````

`flow` and `eslint` checks are available:

``````\$ make lint        # eslint checks
\$ make flow        # make lint + Flow checking
\$ make tslint      # check TS definitions
``````

### Browser

(click to show)

The core in-browser tests are available at `tests/index.html` within this repo. Start a local server and navigate to that directory to run the tests. `make ctestserv` will start a server on port 8000.

`make ctest` will generate the browser fixtures. To add more files, edit the `tests/fixtures.lst` file and add the paths.

To run the full in-browser tests, clone the repo for `oss.sheetjs.com` and replace the `xlsx.js` file (then open a browser window and go to `stress.html`):

``````\$ cp xlsx.js ../SheetJS.github.io
\$ cd ../SheetJS.github.io
\$ simplehttpserver # or "python -mSimpleHTTPServer" or "serve"
\$ open -a Chromium.app http://localhost:8000/stress.html
``````

### Tested Environments

(click to show)

• NodeJS `0.8`, `0.10`, `0.12`, `4.x`, `5.x`, `6.x`, `7.x`, `8.x`
• IE 6/7/8/9/10/11 (IE 6-9 require shims)
• Chrome 24+ (including Android 4.0+)
• Safari 6+ (iOS and Desktop)
• Edge 13+, FF 18+, and Opera 12+

Tests utilize the mocha testing framework.

The test suite also includes tests for various time zones. To change the timezone locally, set the TZ environment variable:

``````\$ env TZ="Asia/Kolkata" WTF=1 make test_misc
``````

### Test Files

Test files are housed in another repo.

Running `make init` will refresh the `test_files` submodule and get the files. Note that this requires `svn`, `git`, `hg` and other commands that may not be available. If `make init` fails, please download the latest version of the test files snapshot from the repo

Latest Snapshot (click to show)

(download and unzip to the `test_files` subdirectory)

## Contributing

Due to the precarious nature of the Open Specifications Promise, it is very important to ensure code is cleanroom. Contribution Notes

File organization (click to show)

At a high level, the final script is a concatenation of the individual files in the `bits` folder. Running `make` should reproduce the final output on all platforms. The README is similarly split into bits in the `docbits` folder.

Folders:

After cloning the repo, running `make help` will display a list of commands.

### OSX/Linux

(click to show)

The `xlsx.js` file is constructed from the files in the `bits` subdirectory. The build script (run `make`) will concatenate the individual bits to produce the script. Before submitting a contribution, ensure that running make will produce the `xlsx.js` file exactly. The simplest way to test is to add the script:

``````\$ git add xlsx.js
\$ make clean
\$ make
\$ git diff xlsx.js
``````

To produce the dist files, run `make dist`. The dist files are updated in each version release and should not be committed between versions.

### Windows

(click to show)

The included `make.cmd` script will build `xlsx.js` from the `bits` directory. Building is as simple as:

``````> make
``````

To prepare development environment:

``````> make init
``````

The full list of commands available in Windows are displayed in `make help`:

``````make init -- install deps and global modules
make lint -- run eslint linter
make test -- run mocha test suite
make misc -- run smaller test suite
make book -- rebuild README and summary
make help -- display this message
``````

As explained in Test Files, on Windows the release ZIP file must be downloaded and extracted. If Bash on Windows is available, it is possible to run the OSX/Linux workflow. The following steps prepares the environment:

``````# Install support programs for the build and test commands
sudo apt-get install make git subversion mercurial

# Install nodejs and NPM within the WSL
wget -qO- https://deb.nodesource.com/setup_8.x | sudo bash
sudo apt-get install nodejs

# Install dev dependencies
sudo npm install -g mocha voc blanket xlsjs
``````

### Tests

(click to show)

The `test_misc` target (`make test_misc` on Linux/OSX / `make misc` on Windows) runs the targeted feature tests. It should take 5-10 seconds to perform feature tests without testing against the entire test battery. New features should be accompanied with tests for the relevant file formats and features.

For tests involving the read side, an appropriate feature test would involve reading an existing file and checking the resulting workbook object. If a parameter is involved, files should be read with different values to verify that the feature is working as expected.

For tests involving a new write feature which can already be parsed, appropriate feature tests would involve writing a workbook with the feature and then opening and verifying that the feature is preserved.

For tests involving a new write feature without an existing read ability, please add a feature test to the kitchen sink `tests/write.js`.

## References

OSP-covered Specifications (click to show)

• `MS-CFB`: Compound File Binary File Format
• `MS-CTXLS`: Excel Custom Toolbar Binary File Format
• `MS-EXSPXML3`: Excel Calculation Version 2 Web Service XML Schema
• `MS-ODATA`: Open Data Protocol (OData)
• `MS-ODRAW`: Office Drawing Binary File Format
• `MS-ODRAWXML`: Office Drawing Extensions to Office Open XML Structure
• `MS-OE376`: Office Implementation Information for ECMA-376 Standards Support
• `MS-OFFCRYPTO`: Office Document Cryptography Structure
• `MS-OI29500`: Office Implementation Information for ISO/IEC 29500 Standards Support
• `MS-OLEDS`: Object Linking and Embedding (OLE) Data Structures
• `MS-OLEPS`: Object Linking and Embedding (OLE) Property Set Data Structures
• `MS-OODF3`: Office Implementation Information for ODF 1.2 Standards Support
• `MS-OSHARED`: Office Common Data Types and Objects Structures
• `MS-OVBA`: Office VBA File Format Structure
• `MS-XLDM`: Spreadsheet Data Model File Format
• `MS-XLS`: Excel Binary File Format (.xls) Structure Specification
• `MS-XLSB`: Excel (.xlsb) Binary File Format
• `MS-XLSX`: Excel (.xlsx) Extensions to the Office Open XML SpreadsheetML File Format
• `XLS`: Microsoft Office Excel 97-2007 Binary File Format Specification
• `RTF`: Rich Text Format
• ISO/IEC 29500:2012(E) "Information technology — Document description and processing languages — Office Open XML File Formats"
• Open Document Format for Office Applications Version 1.2 (29 September 2011)
• Worksheet File Format (From Lotus) December 1984

Browser Test and Support Matrix

Supported File Formats

Author: SheetJS
Source Code: https://github.com/SheetJS/sheetjs

1643018220

## SheetJS

Parser and writer for various spreadsheet formats. Pure-JS cleanroom implementation from official specifications, related documents, and test files. Emphasis on parsing and writing robustness, cross-format feature compatibility with a unified JS representation, and ES3/ES5 browser compatibility back to IE6.

This is the community version. We also offer a pro version with performance enhancements, additional features like styling, and dedicated support.

Community Translations of this README:

Supported File Formats

Diagram Legend (click to show)

## Installation

In the browser, just add a script tag:

``````<script lang="javascript" src="dist/xlsx.full.min.js"></script>
``````

CDN Availability (click to show)

`unpkg` makes the latest version available at:

``````<script src="https://unpkg.com/xlsx/dist/xlsx.full.min.js"></script>
``````

With npm:

``````\$ npm install xlsx
``````

With bower:

``````\$ bower install js-xlsx
``````

### JS Ecosystem Demos

The `demos` directory includes sample projects for:

Frameworks and APIs

Bundlers and Tooling

Platforms and Integrations

Other examples are included in the showcase.

### Optional Modules

Optional features (click to show)

The node version automatically requires modules for additional features. Some of these modules are rather large in size and are only needed in special circumstances, so they do not ship with the core. For browser use, they must be included directly:

``````<!-- international support from js-codepage -->
<script src="dist/cpexcel.js"></script>
``````

An appropriate version for each dependency is included in the dist/ directory.

The complete single-file version is generated at `dist/xlsx.full.min.js`

A slimmer build is generated at `dist/xlsx.mini.min.js`. Compared to full build:

• codepage library skipped (no support for XLS encodings)
• XLSX compression option not currently available
• no support for XLSB / XLS / Lotus 1-2-3 / SpreadsheetML 2003
• node stream utils removed

Webpack and Browserify builds include optional modules by default. Webpack can be configured to remove support with `resolve.alias`:

``````  /* uncomment the lines below to remove support */
resolve: {
alias: { "./dist/cpexcel.js": "" } // <-- omit international support
}
``````

### ECMAScript 5 Compatibility

Since the library uses functions like `Array#forEach`, older browsers require shims to provide missing functions.

To use the shim, add the shim before the script tag that loads `xlsx.js`:

``````<!-- add the shim first -->
<script type="text/javascript" src="shim.min.js"></script>
<!-- after the shim is referenced, add the library -->
<script type="text/javascript" src="xlsx.full.min.js"></script>
``````

The script also includes `IE_LoadFile` and `IE_SaveFile` for loading and saving files in Internet Explorer versions 6-9. The `xlsx.extendscript.js` script bundles the shim in a format suitable for Photoshop and other Adobe products.

## Philosophy

Philosophy (click to show)

Prior to SheetJS, APIs for processing spreadsheet files were format-specific. Third-party libraries either supported one format, or they involved a separate set of classes for each supported file type. Even though XLSB was introduced in Excel 2007, nothing outside of SheetJS or Excel supported the format.

To promote a format-agnostic view, SheetJS starts from a pure-JS representation that we call the "Common Spreadsheet Format". Emphasizing a uniform object representation enables new features like format conversion (reading an XLSX template and saving as XLS) and circumvents the mess of classes. By abstracting the complexities of the various formats, tools need not worry about the specific file type!

A simple object representation combined with careful coding practices enables use cases in older browsers and in alternative environments like ExtendScript and Web Workers. It is always tempting to use the latest and greatest features, but they tend to require the latest versions of browsers, limiting usability.

Utility functions capture common use cases like generating JS objects or HTML. Most simple operations should only require a few lines of code. More complex operations generally should be straightforward to implement.

Excel pushes the XLSX format as default starting in Excel 2007. However, there are other formats with more appealing properties. For example, the XLSB format is spiritually similar to XLSX but files often tend up taking less than half the space and open much faster! Even though an XLSX writer is available, other format writers are available so users can take advantage of the unique characteristics of each format.

The primary focus of the Community Edition is correct data interchange, focused on extracting data from any compatible data representation and exporting data in various formats suitable for any third party interface.

## Parsing Workbooks

For parsing, the first step is to read the file. This involves acquiring the data and feeding it into the library. Here are a few common scenarios:

nodejs read a file (click to show)

`readFile` is only available in server environments. Browsers have no API for reading arbitrary files given a path, so another strategy must be used.

``````if(typeof require !== 'undefined') XLSX = require('xlsx');
var workbook = XLSX.readFile('test.xlsx');
/* DO SOMETHING WITH workbook HERE */
``````

Photoshop ExtendScript read a file (click to show)

`readFile` wraps the `File` logic in Photoshop and other ExtendScript targets. The specified path should be an absolute path:

``````#include "xlsx.extendscript.js"
/* Read test.xlsx from the Documents folder */
var workbook = XLSX.readFile(Folder.myDocuments + '/' + 'test.xlsx');
/* DO SOMETHING WITH workbook HERE */
``````

The `extendscript` demo includes a more complex example.

Browser read TABLE element from page (click to show)

The `table_to_book` and `table_to_sheet` utility functions take a DOM TABLE element and iterate through the child nodes.

``````var workbook = XLSX.utils.table_to_book(document.getElementById('tableau'));
/* DO SOMETHING WITH workbook HERE */
``````

Multiple tables on a web page can be converted to individual worksheets:

``````/* create new workbook */
var workbook = XLSX.utils.book_new();

/* convert table 'table1' to worksheet named "Sheet1" */
var ws1 = XLSX.utils.table_to_sheet(document.getElementById('table1'));
XLSX.utils.book_append_sheet(workbook, ws1, "Sheet1");

/* convert table 'table2' to worksheet named "Sheet2" */
var ws2 = XLSX.utils.table_to_sheet(document.getElementById('table2'));
XLSX.utils.book_append_sheet(workbook, ws2, "Sheet2");

/* workbook now has 2 worksheets */
``````

Alternatively, the HTML code can be extracted and parsed:

``````var htmlstr = document.getElementById('tableau').outerHTML;
var workbook = XLSX.read(htmlstr, {type:'string'});
``````

Browser download file (ajax) (click to show)

Note: for a more complete example that works in older browsers, check the demo at http://oss.sheetjs.com/sheetjs/ajax.html. The `xhr` demo includes more examples with `XMLHttpRequest` and `fetch`.

``````var url = "http://oss.sheetjs.com/test_files/formula_stress_test.xlsx";

/* set up async GET request */
var req = new XMLHttpRequest();
req.open("GET", url, true);
req.responseType = "arraybuffer";

req.onload = function(e) {
var workbook = XLSX.read(req.response);

/* DO SOMETHING WITH workbook HERE */
}

req.send();
``````

Browser drag-and-drop (click to show)

For modern browsers, `Blob#arrayBuffer` can read data from files:

``````async function handleDropAsync(e) {
e.stopPropagation(); e.preventDefault();
const f = evt.dataTransfer.files[0];
const data = await f.arrayBuffer();
const workbook = XLSX.read(data);

/* DO SOMETHING WITH workbook HERE */
}
``````

For maximal compatibility, the `FileReader` API should be used:

``````function handleDrop(e) {
e.stopPropagation(); e.preventDefault();
var f = e.dataTransfer.files[0];
var workbook = XLSX.read(e.target.result);

/* DO SOMETHING WITH workbook HERE */
};
}
``````

Browser file upload form element (click to show)

Data from file input elements can be processed using the same APIs as in the drag-and-drop example.

Using `Blob#arrayBuffer`:

``````async function handleFileAsync(e) {
const file = e.target.files[0];
const data = await file.arrayBuffer();
const workbook = XLSX.read(data);

/* DO SOMETHING WITH workbook HERE */
}
``````

Using `FileReader`:

``````function handleFile(e) {
var files = e.target.files, f = files[0];
var workbook = XLSX.read(e.target.result);

/* DO SOMETHING WITH workbook HERE */
};
}
``````

The `oldie` demo shows an IE-compatible fallback scenario.

More specialized cases, including mobile app file processing, are covered in the included demos

### Parsing Examples

Note that older versions of IE do not support HTML5 File API, so the Base64 mode is used for testing.

Get Base64 encoding on OSX / Windows (click to show)

On OSX you can get the Base64 encoding with:

``````\$ <target_file base64 | pbcopy
``````

On Windows XP and up you can get the Base64 encoding using `certutil`:

``````> certutil -encode target_file target_file.b64
``````

(note: You have to open the file and remove the header and footer lines)

Why is there no Streaming Read API? (click to show)

The most common and interesting formats (XLS, XLSX/M, XLSB, ODS) are ultimately ZIP or CFB containers of files. Neither format puts the directory structure at the beginning of the file: ZIP files place the Central Directory records at the end of the logical file, while CFB files can place the storage info anywhere in the file! As a result, to properly handle these formats, a streaming function would have to buffer the entire file before commencing. That belies the expectations of streaming, so we do not provide any streaming read API.

When dealing with Readable Streams, the easiest approach is to buffer the stream and process the whole thing at the end. This can be done with a temporary file or by explicitly concatenating the stream:

Explicitly concatenating streams (click to show)

``````var fs = require('fs');
var XLSX = require('xlsx');
var buffers = [];
stream.on('data', function(data) { buffers.push(data); });
stream.on('end', function() {
var buffer = Buffer.concat(buffers);
var workbook = XLSX.read(buffer, {type:"buffer"});

/* DO SOMETHING WITH workbook IN THE CALLBACK */
cb(workbook);
});
}
``````

More robust solutions are available using modules like `concat-stream`.

Writing to filesystem first (click to show)

This example uses `tempfile` to generate file names:

``````var fs = require('fs'), tempfile = require('tempfile');
var XLSX = require('xlsx');
var fname = tempfile('.sheetjs');
console.log(fname);
var ostream = fs.createWriteStream(fname);
stream.pipe(ostream);
ostream.on('finish', function() {
var workbook = XLSX.readFile(fname);

/* DO SOMETHING WITH workbook IN THE CALLBACK */
cb(workbook);
});
}
``````

## Working with the Workbook

The full object format is described later in this README.

Reading a specific cell (click to show)

This example extracts the value stored in cell A1 from the first worksheet:

``````var first_sheet_name = workbook.SheetNames[0];
var address_of_cell = 'A1';

/* Get worksheet */
var worksheet = workbook.Sheets[first_sheet_name];

/* Find desired cell */
var desired_cell = worksheet[address_of_cell];

/* Get the value */
var desired_value = (desired_cell ? desired_cell.v : undefined);
``````

Adding a new worksheet to a workbook (click to show)

This example uses `XLSX.utils.aoa_to_sheet` to make a sheet and `XLSX.utils.book_append_sheet` to append the sheet to the workbook:

``````var ws_name = "SheetJS";

/* make worksheet */
var ws_data = [
[ "S", "h", "e", "e", "t", "J", "S" ],
[  1 ,  2 ,  3 ,  4 ,  5 ]
];
var ws = XLSX.utils.aoa_to_sheet(ws_data);

/* Add the worksheet to the workbook */
XLSX.utils.book_append_sheet(wb, ws, ws_name);
``````

Creating a new workbook from scratch (click to show)

The workbook object contains a `SheetNames` array of names and a `Sheets` object mapping sheet names to sheet objects. The `XLSX.utils.book_new` utility function creates a new workbook object:

``````/* create a new blank workbook */
var wb = XLSX.utils.book_new();
``````

The new workbook is blank and contains no worksheets. The write functions will error if the workbook is empty.

### Parsing and Writing Examples

https://sheetjs.com/demos/modify.html read + modify + write files

The node version installs a command line tool `xlsx` which can read spreadsheet files and output the contents in various formats. The source is available at `xlsx.njs` in the bin directory.

Some helper functions in `XLSX.utils` generate different views of the sheets:

• `XLSX.utils.sheet_to_csv` generates CSV
• `XLSX.utils.sheet_to_txt` generates UTF16 Formatted Text
• `XLSX.utils.sheet_to_html` generates HTML
• `XLSX.utils.sheet_to_json` generates an array of objects
• `XLSX.utils.sheet_to_formulae` generates a list of formulae

## Writing Workbooks

For writing, the first step is to generate output data. The helper functions `write` and `writeFile` will produce the data in various formats suitable for dissemination. The second step is to actual share the data with the end point. Assuming `workbook` is a workbook object:

nodejs write a file (click to show)

`XLSX.writeFile` uses `fs.writeFileSync` in server environments:

``````if(typeof require !== 'undefined') XLSX = require('xlsx');
/* output format determined by filename */
XLSX.writeFile(workbook, 'out.xlsb');
/* at this point, out.xlsb is a file that you can distribute */
``````

Photoshop ExtendScript write a file (click to show)

`writeFile` wraps the `File` logic in Photoshop and other ExtendScript targets. The specified path should be an absolute path:

``````#include "xlsx.extendscript.js"
/* output format determined by filename */
XLSX.writeFile(workbook, 'out.xlsx');
/* at this point, out.xlsx is a file that you can distribute */
``````

The `extendscript` demo includes a more complex example.

Browser add TABLE element to page (click to show)

The `sheet_to_html` utility function generates HTML code that can be added to any DOM element.

``````var worksheet = workbook.Sheets[workbook.SheetNames[0]];
var container = document.getElementById('tableau');
container.innerHTML = XLSX.utils.sheet_to_html(worksheet);
``````

Browser upload file (ajax) (click to show)

A complete example using XHR is included in the XHR demo, along with examples for fetch and wrapper libraries. This example assumes the server can handle Base64-encoded files (see the demo for a basic nodejs server):

``````/* in this example, send a base64 string to the server */
var wopts = { bookType:'xlsx', bookSST:false, type:'base64' };

var wbout = XLSX.write(workbook,wopts);

var req = new XMLHttpRequest();
var formdata = new FormData();
formdata.append('file', 'test.xlsx'); // <-- server expects `file` to hold name
formdata.append('data', wbout); // <-- `data` holds the base64-encoded data
req.send(formdata);
``````

Browser save file (click to show)

`XLSX.writeFile` wraps a few techniques for triggering a file save:

• `URL` browser API creates an object URL for the file, which the library uses by creating a link and forcing a click. It is supported in modern browsers.
• `msSaveBlob` is an IE10+ API for triggering a file save.
• `IE_FileSave` uses VBScript and ActiveX to write a file in IE6+ for Windows XP and Windows 7. The shim must be included in the containing HTML page.

There is no standard way to determine if the actual file has been downloaded.

``````/* output format determined by filename */
XLSX.writeFile(workbook, 'out.xlsb');
/* at this point, out.xlsb will have been downloaded */
``````

Browser save file (compatibility) (click to show)

`XLSX.writeFile` techniques work for most modern browsers as well as older IE. For much older browsers, there are workarounds implemented by wrapper libraries.

`FileSaver.js` implements `saveAs`. Note: `XLSX.writeFile` will automatically call `saveAs` if available.

``````/* bookType can be any supported output type */
var wopts = { bookType:'xlsx', bookSST:false, type:'array' };

var wbout = XLSX.write(workbook,wopts);

/* the saveAs call downloads a file on the local machine */
saveAs(new Blob([wbout],{type:"application/octet-stream"}), "test.xlsx");
``````

`Downloadify` uses a Flash SWF button to generate local files, suitable for environments where ActiveX is unavailable:

``````Downloadify.create(id,{
filename: "test.xlsx",
data: function() { return XLSX.write(wb, {bookType:"xlsx", type:'base64'}); },
append: false,
dataType: 'base64'
});
``````

The `oldie` demo shows an IE-compatible fallback scenario.

The included demos cover mobile apps and other special deployments.

### Streaming Write

The streaming write functions are available in the `XLSX.stream` object. They take the same arguments as the normal write functions but return a Readable Stream. They are only exposed in NodeJS.

• `XLSX.stream.to_csv` is the streaming version of `XLSX.utils.sheet_to_csv`.
• `XLSX.stream.to_html` is the streaming version of `XLSX.utils.sheet_to_html`.
• `XLSX.stream.to_json` is the streaming version of `XLSX.utils.sheet_to_json`.

nodejs convert to CSV and write file (click to show)

``````var output_file_name = "out.csv";
var stream = XLSX.stream.to_csv(worksheet);
stream.pipe(fs.createWriteStream(output_file_name));
``````

nodejs write JSON stream to screen (click to show)

``````/* to_json returns an object-mode stream */
var stream = XLSX.stream.to_json(worksheet, {raw:true});

/* the following stream converts JS objects to text via JSON.stringify */
var conv = new Transform({writableObjectMode:true});
conv._transform = function(obj, e, cb){ cb(null, JSON.stringify(obj) + "\n"); };

stream.pipe(conv); conv.pipe(process.stdout);
``````

https://github.com/sheetjs/sheetaki pipes write streams to nodejs response.

## Interface

`XLSX` is the exposed variable in the browser and the exported node variable

`XLSX.version` is the version of the library (added by the build script).

`XLSX.SSF` is an embedded version of the format library.

### Parsing functions

`XLSX.read(data, read_opts)` attempts to parse `data`.

`XLSX.readFile(filename, read_opts)` attempts to read `filename` and parse.

Parse options are described in the Parsing Options section.

### Writing functions

`XLSX.write(wb, write_opts)` attempts to write the workbook `wb`

`XLSX.writeFile(wb, filename, write_opts)` attempts to write `wb` to `filename`. In browser-based environments, it will attempt to force a client-side download.

`XLSX.writeFileAsync(wb, filename, o, cb)` attempts to write `wb` to `filename`. If `o` is omitted, the writer will use the third argument as the callback.

`XLSX.stream` contains a set of streaming write functions.

Write options are described in the Writing Options section.

### Utilities

Utilities are available in the `XLSX.utils` object and are described in the Utility Functions section:

Importing:

• `aoa_to_sheet` converts an array of arrays of JS data to a worksheet.
• `json_to_sheet` converts an array of JS objects to a worksheet.
• `table_to_sheet` converts a DOM TABLE element to a worksheet.
• `sheet_add_aoa` adds an array of arrays of JS data to an existing worksheet.
• `sheet_add_json` adds an array of JS objects to an existing worksheet.

Exporting:

• `sheet_to_json` converts a worksheet object to an array of JSON objects.
• `sheet_to_csv` generates delimiter-separated-values output.
• `sheet_to_txt` generates UTF16 formatted text.
• `sheet_to_html` generates HTML output.
• `sheet_to_formulae` generates a list of the formulae (with value fallbacks).

Cell and cell address manipulation:

• `format_cell` generates the text value for a cell (using number formats).
• `encode_row / decode_row` converts between 0-indexed rows and 1-indexed rows.
• `encode_col / decode_col` converts between 0-indexed columns and column names.
• `encode_cell / decode_cell` converts cell addresses.
• `encode_range / decode_range` converts cell ranges.

## Common Spreadsheet Format

SheetJS conforms to the Common Spreadsheet Format (CSF):

### General Structures

Cell address objects are stored as `{c:C, r:R}` where `C` and `R` are 0-indexed column and row numbers, respectively. For example, the cell address `B5` is represented by the object `{c:1, r:4}`.

Cell range objects are stored as `{s:S, e:E}` where `S` is the first cell and `E` is the last cell in the range. The ranges are inclusive. For example, the range `A3:B7` is represented by the object `{s:{c:0, r:2}, e:{c:1, r:6}}`. Utility functions perform a row-major order walk traversal of a sheet range:

``````for(var R = range.s.r; R <= range.e.r; ++R) {
for(var C = range.s.c; C <= range.e.c; ++C) {
var cell_address = {c:C, r:R};
/* if an A1-style address is needed, encode the address */
var cell_ref = XLSX.utils.encode_cell(cell_address);
}
}
``````

### Cell Object

Cell objects are plain JS objects with keys and values following the convention:

Built-in export utilities (such as the CSV exporter) will use the `w` text if it is available. To change a value, be sure to delete `cell.w` (or set it to `undefined`) before attempting to export. The utilities will regenerate the `w` text from the number format (`cell.z`) and the raw value if possible.

The actual array formula is stored in the `f` field of the first cell in the array range. Other cells in the range will omit the `f` field.

#### Data Types

The raw value is stored in the `v` value property, interpreted based on the `t` type property. This separation allows for representation of numbers as well as numeric text. There are 6 valid cell types:

Error values and interpretation (click to show)

Type `n` is the Number type. This includes all forms of data that Excel stores as numbers, such as dates/times and Boolean fields. Excel exclusively uses data that can be fit in an IEEE754 floating point number, just like JS Number, so the `v` field holds the raw number. The `w` field holds formatted text. Dates are stored as numbers by default and converted with `XLSX.SSF.parse_date_code`.

Type `d` is the Date type, generated only when the option `cellDates` is passed. Since JSON does not have a natural Date type, parsers are generally expected to store ISO 8601 Date strings like you would get from `date.toISOString()`. On the other hand, writers and exporters should be able to handle date strings and JS Date objects. Note that Excel disregards timezone modifiers and treats all dates in the local timezone. The library does not correct for this error.

Type `s` is the String type. Values are explicitly stored as text. Excel will interpret these cells as "number stored as text". Generated Excel files automatically suppress that class of error, but other formats may elicit errors.

Type `z` represents blank stub cells. They are generated in cases where cells have no assigned value but hold comments or other metadata. They are ignored by the core library data processing utility functions. By default these cells are not generated; the parser `sheetStubs` option must be set to `true`.

#### Dates

Excel Date Code details (click to show)

By default, Excel stores dates as numbers with a format code that specifies date processing. For example, the date `19-Feb-17` is stored as the number `42785` with a number format of `d-mmm-yy`. The `SSF` module understands number formats and performs the appropriate conversion.

XLSX also supports a special date type `d` where the data is an ISO 8601 date string. The formatter converts the date back to a number.

The default behavior for all parsers is to generate number cells. Setting `cellDates` to true will force the generators to store dates.

Time Zones and Dates (click to show)

Excel has no native concept of universal time. All times are specified in the local time zone. Excel limitations prevent specifying true absolute dates.

Following Excel, this library treats all dates as relative to local time zone.

Epochs: 1900 and 1904 (click to show)

Excel supports two epochs (January 1 1900 and January 1 1904). The workbook's epoch can be determined by examining the workbook's `wb.Workbook.WBProps.date1904` property:

``````!!(((wb.Workbook||{}).WBProps||{}).date1904)
``````

### Sheet Objects

Each key that does not start with `!` maps to a cell (using `A-1` notation)

`sheet[address]` returns the cell object for the specified address.

Special sheet keys (accessible as `sheet[key]`, each starting with `!`):

`sheet['!ref']`: A-1 based range representing the sheet range. Functions that work with sheets should use this parameter to determine the range. Cells that are assigned outside of the range are not processed. In particular, when writing a sheet by hand, cells outside of the range are not included

Functions that handle sheets should test for the presence of `!ref` field. If the `!ref` is omitted or is not a valid range, functions are free to treat the sheet as empty or attempt to guess the range. The standard utilities that ship with this library treat sheets as empty (for example, the CSV output is empty string).

When reading a worksheet with the `sheetRows` property set, the ref parameter will use the restricted range. The original range is set at `ws['!fullref']`

`sheet['!margins']`: Object representing the page margins. The default values follow Excel's "normal" preset. Excel also has a "wide" and a "narrow" preset but they are stored as raw measurements. The main properties are listed below:

Page margin details (click to show)

``````/* Set worksheet sheet to "normal" */
/* Set worksheet sheet to "wide" */
ws["!margins"]={left:1.0, right:1.0, top:1.0, bottom:1.0, header:0.5,footer:0.5}
/* Set worksheet sheet to "narrow" */
``````

#### Worksheet Object

In addition to the base sheet keys, worksheets also add:

`ws['!cols']`: array of column properties objects. Column widths are actually stored in files in a normalized manner, measured in terms of the "Maximum Digit Width" (the largest width of the rendered digits 0-9, in pixels). When parsed, the column objects store the pixel width in the `wpx` field, character width in the `wch` field, and the maximum digit width in the `MDW` field.

`ws['!rows']`: array of row properties objects as explained later in the docs. Each row object encodes properties including row height and visibility.

`ws['!merges']`: array of range objects corresponding to the merged cells in the worksheet. Plain text formats do not support merge cells. CSV export will write all cells in the merge range if they exist, so be sure that only the first cell (upper-left) in the range is set.

`ws['!outline']`: configure how outlines should behave. Options default to the default settings in Excel 2019:

• `ws['!protect']`: object of write sheet protection properties. The `password` key specifies the password for formats that support password-protected sheets (XLSX/XLSB/XLS). The writer uses the XOR obfuscation method. The following keys control the sheet protection -- set to `false` to enable a feature when sheet is locked or set to `true` to disable a feature:

Worksheet Protection Details (click to show)

• `ws['!autofilter']`: AutoFilter object following the schema:
``````type AutoFilter = {
ref:string; // A-1 based range representing the AutoFilter table range
}
``````

#### Chartsheet Object

Chartsheets are represented as standard sheets. They are distinguished with the `!type` property set to `"chart"`.

The underlying data and `!ref` refer to the cached data in the chartsheet. The first row of the chartsheet is the underlying header.

#### Macrosheet Object

Macrosheets are represented as standard sheets. They are distinguished with the `!type` property set to `"macro"`.

#### Dialogsheet Object

Dialogsheets are represented as standard sheets. They are distinguished with the `!type` property set to `"dialog"`.

### Workbook Object

`workbook.SheetNames` is an ordered list of the sheets in the workbook

`wb.Sheets[sheetname]` returns an object representing the worksheet.

`wb.Props` is an object storing the standard properties. `wb.Custprops` stores custom properties. Since the XLS standard properties deviate from the XLSX standard, XLS parsing stores core properties in both places.

`wb.Workbook` stores workbook-level attributes.

#### Workbook File Properties

The various file formats use different internal names for file properties. The workbook `Props` object normalizes the names:

File Properties (click to show)

For example, to set the workbook title property:

``````if(!wb.Props) wb.Props = {};
wb.Props.Title = "Insert Title Here";
``````

Custom properties are added in the workbook `Custprops` object:

``````if(!wb.Custprops) wb.Custprops = {};
wb.Custprops["Custom Property"] = "Custom Value";
``````

Writers will process the `Props` key of the options object:

``````/* force the Author to be "SheetJS" */
XLSX.write(wb, {Props:{Author:"SheetJS"}});
``````

### Workbook-Level Attributes

`wb.Workbook` stores workbook-level attributes.

#### Defined Names

`wb.Workbook.Names` is an array of defined name objects which have the keys:

Defined Name Properties (click to show)

Excel allows two sheet-scoped defined names to share the same name. However, a sheet-scoped name cannot collide with a workbook-scope name. Workbook writers may not enforce this constraint.

#### Workbook Views

`wb.Workbook.Views` is an array of workbook view objects which have the keys:

#### Miscellaneous Workbook Properties

`wb.Workbook.WBProps` holds other workbook properties:

### Document Features

Even for basic features like date storage, the official Excel formats store the same content in different ways. The parsers are expected to convert from the underlying file format representation to the Common Spreadsheet Format. Writers are expected to convert from CSF back to the underlying file format.

#### Formulae

The A1-style formula string is stored in the `f` field. Even though different file formats store the formulae in different ways, the formats are translated. Even though some formats store formulae with a leading equal sign, CSF formulae do not start with `=`.

Representation of A1=1, A2=2, A3=A1+A2 (click to show)

``````{
"!ref": "A1:A3",
A1: { t:'n', v:1 },
A2: { t:'n', v:2 },
A3: { t:'n', v:3, f:'A1+A2' }
}
``````

Shared formulae are decompressed and each cell has the formula corresponding to its cell. Writers generally do not attempt to generate shared formulae.

Cells with formula entries but no value will be serialized in a way that Excel and other spreadsheet tools will recognize. This library will not automatically compute formula results! For example, to compute `BESSELJ` in a worksheet:

Formula without known value (click to show)

``````{
"!ref": "A1:A3",
A1: { t:'n', v:3.14159 },
A2: { t:'n', v:2 },
A3: { t:'n', f:'BESSELJ(A1,A2)' }
}
``````

Array Formulae

Array formulae are stored in the top-left cell of the array block. All cells of an array formula have a `F` field corresponding to the range. A single-cell formula can be distinguished from a plain formula by the presence of `F` field.

Array Formula examples (click to show)

For example, setting the cell `C1` to the array formula `{=SUM(A1:A3*B1:B3)}`:

``````worksheet['C1'] = { t:'n', f: "SUM(A1:A3*B1:B3)", F:"C1:C1" };
``````

For a multi-cell array formula, every cell has the same array range but only the first cell specifies the formula. Consider `D1:D3=A1:A3*B1:B3`:

``````worksheet['D1'] = { t:'n', F:"D1:D3", f:"A1:A3*B1:B3" };
worksheet['D2'] = { t:'n', F:"D1:D3" };
worksheet['D3'] = { t:'n', F:"D1:D3" };
``````

Utilities and writers are expected to check for the presence of a `F` field and ignore any possible formula element `f` in cells other than the starting cell. They are not expected to perform validation of the formulae!

Formula Output Utility Function (click to show)

The `sheet_to_formulae` method generates one line per formula or array formula. Array formulae are rendered in the form `range=formula` while plain cells are rendered in the form `cell=formula or value`. Note that string literals are prefixed with an apostrophe `'`, consistent with Excel's formula bar display.

Formulae File Format Details (click to show)

Since Excel prohibits named cells from colliding with names of A1 or RC style cell references, a (not-so-simple) regex conversion is possible. BIFF Parsed formulae and Lotus Parsed formulae have to be explicitly unwound. OpenFormula formulae can be converted with regular expressions.

#### Column Properties

The `!cols` array in each worksheet, if present, is a collection of `ColInfo` objects which have the following properties:

``````type ColInfo = {
/* visibility */
hidden?: boolean; // if true, the column is hidden

/* column width is specified in one of the following ways: */
wpx?:    number;  // width in screen pixels
width?:  number;  // width in Excel's "Max Digit Width", width*256 is integral
wch?:    number;  // width in characters

/* other fields for preserving features from files */
level?:  number;  // 0-indexed outline / group level
MDW?:    number;  // Excel's "Max Digit Width" unit, always integral
};
``````

Why are there three width types? (click to show)

There are three different width types corresponding to the three different ways spreadsheets store column widths:

SYLK and other plain text formats use raw character count. Contemporaneous tools like Visicalc and Multiplan were character based. Since the characters had the same width, it sufficed to store a count. This tradition was continued into the BIFF formats.

SpreadsheetML (2003) tried to align with HTML by standardizing on screen pixel count throughout the file. Column widths, row heights, and other measures use pixels. When the pixel and character counts do not align, Excel rounds values.

XLSX internally stores column widths in a nebulous "Max Digit Width" form. The Max Digit Width is the width of the largest digit when rendered (generally the "0" character is the widest). The internal width must be an integer multiple of the the width divided by 256. ECMA-376 describes a formula for converting between pixels and the internal width. This represents a hybrid approach.

Read functions attempt to populate all three properties. Write functions will try to cycle specified values to the desired type. In order to avoid potential conflicts, manipulation should delete the other properties first. For example, when changing the pixel width, delete the `wch` and `width` properties.

Implementation details (click to show)

Given the constraints, it is possible to determine the MDW without actually inspecting the font! The parsers guess the pixel width by converting from width to pixels and back, repeating for all possible MDW and selecting the MDW that minimizes the error. XLML actually stores the pixel width, so the guess works in the opposite direction.

Even though all of the information is made available, writers are expected to follow the priority order:

1. use `width` field if available
2. use `wpx` pixel width if available
3. use `wch` character count if available

#### Row Properties

The `!rows` array in each worksheet, if present, is a collection of `RowInfo` objects which have the following properties:

``````type RowInfo = {
/* visibility */
hidden?: boolean; // if true, the row is hidden

/* row height is specified in one of the following ways: */
hpx?:    number;  // height in screen pixels
hpt?:    number;  // height in points

level?:  number;  // 0-indexed outline / group level
};
``````

Note: Excel UI displays the base outline level as `1` and the max level as `8`. The `level` field stores the base outline as `0` and the max level as `7`.

Implementation details (click to show)

Excel internally stores row heights in points. The default resolution is 72 DPI or 96 PPI, so the pixel and point size should agree. For different resolutions they may not agree, so the library separates the concepts.

Even though all of the information is made available, writers are expected to follow the priority order:

1. use `hpx` pixel height if available
2. use `hpt` point height if available

#### Number Formats

The `cell.w` formatted text for each cell is produced from `cell.v` and `cell.z` format. If the format is not specified, the Excel `General` format is used. The format can either be specified as a string or as an index into the format table. Parsers are expected to populate `workbook.SSF` with the number format table. Writers are expected to serialize the table.

Custom tools should ensure that the local table has each used format string somewhere in the table. Excel convention mandates that the custom formats start at index 164. The following example creates a custom format from scratch:

New worksheet with custom format (click to show)

``````var wb = {
SheetNames: ["Sheet1"],
Sheets: {
Sheet1: {
"!ref":"A1:C1",
A1: { t:"n", v:10000 },                    // <-- General format
B1: { t:"n", v:10000, z: "0%" },           // <-- Builtin format
C1: { t:"n", v:10000, z: "\"T\"\ #0.00" }  // <-- Custom format
}
}
}
``````

The rules are slightly different from how Excel displays custom number formats. In particular, literal characters must be wrapped in double quotes or preceded by a backslash. For more info, see the Excel documentation article `Create or delete a custom number format` or ECMA-376 18.8.31 (Number Formats)

Default Number Formats (click to show)

The default formats are listed in ECMA-376 18.8.30:

Format 14 (`m/d/yy`) is localized by Excel: even though the file specifies that number format, it will be drawn differently based on system settings. It makes sense when the producer and consumer of files are in the same locale, but that is not always the case over the Internet. To get around this ambiguity, parse functions accept the `dateNF` option to override the interpretation of that specific format string.

Format Support (click to show)

Cell Hyperlinks: XLSX/M, XLSB, BIFF8 XLS, XLML, ODS

Tooltips: XLSX/M, XLSB, BIFF8 XLS, XLML

Hyperlinks are stored in the `l` key of cell objects. The `Target` field of the hyperlink object is the target of the link, including the URI fragment. Tooltips are stored in the `Tooltip` field and are displayed when you move your mouse over the text.

For example, the following snippet creates a link from cell `A3` to https://sheetjs.com with the tip `"Find us @ SheetJS.com!"`:

``````ws['A1'].l = { Target:"https://sheetjs.com", Tooltip:"Find us @ SheetJS.com!" };
``````

Note that Excel does not automatically style hyperlinks -- they will generally be displayed as normal text.

HTTP / HTTPS links can be used directly:

``````ws['A2'].l = { Target:"https://docs.sheetjs.com/#hyperlinks" };
ws['A3'].l = { Target:"http://localhost:7262/yes_localhost_works" };
``````

Excel also supports `mailto` email links with subject line:

``````ws['A4'].l = { Target:"mailto:ignored@dev.null" };
ws['A5'].l = { Target:"mailto:ignored@dev.null?subject=Test Subject" };
``````

Links to absolute paths should use the `file://` URI scheme:

``````ws['B1'].l = { Target:"file:///SheetJS/t.xlsx" }; /* Link to /SheetJS/t.xlsx */
ws['B2'].l = { Target:"file:///c:/SheetJS.xlsx" }; /* Link to c:\SheetJS.xlsx */
``````

Links to relative paths can be specified without a scheme:

``````ws['B3'].l = { Target:"SheetJS.xlsb" }; /* Link to SheetJS.xlsb */
ws['B4'].l = { Target:"../SheetJS.xlsm" }; /* Link to ../SheetJS.xlsm */
``````

Relative Paths have undefined behavior in the SpreadsheetML 2003 format. Excel 2019 will treat a `..\` parent mark as two levels up.

Links where the target is a cell or range or defined name in the same workbook ("Internal Links") are marked with a leading hash character:

``````ws['C1'].l = { Target:"#E2" }; /* Link to cell E2 */
ws['C2'].l = { Target:"#Sheet2!E2" }; /* Link to cell E2 in sheet Sheet2 */
ws['C3'].l = { Target:"#SomeDefinedName" }; /* Link to Defined Name */
``````

Cell comments are objects stored in the `c` array of cell objects. The actual contents of the comment are split into blocks based on the comment author. The `a` field of each comment object is the author of the comment and the `t` field is the plain text representation.

For example, the following snippet appends a cell comment into cell `A1`:

``````if(!ws.A1.c) ws.A1.c = [];
ws.A1.c.push({a:"SheetJS", t:"I'm a little comment, short and stout!"});
``````

Note: XLSB enforces a 54 character limit on the Author name. Names longer than 54 characters may cause issues with other formats.

To mark a comment as normally hidden, set the `hidden` property:

``````if(!ws.A1.c) ws.A1.c = [];
ws.A1.c.push({a:"SheetJS", t:"This comment is visible"});

if(!ws.A2.c) ws.A2.c = [];
ws.A2.c.hidden = true;
ws.A2.c.push({a:"SheetJS", t:"This comment will be hidden"});
``````

#### Sheet Visibility

Excel enables hiding sheets in the lower tab bar. The sheet data is stored in the file but the UI does not readily make it available. Standard hidden sheets are revealed in the "Unhide" menu. Excel also has "very hidden" sheets which cannot be revealed in the menu. It is only accessible in the VB Editor!

The visibility setting is stored in the `Hidden` property of sheet props array.

More details (click to show)

``````> wb.Workbook.Sheets.map(function(x) { return [x.name, x.Hidden] })
[ [ 'Visible', 0 ], [ 'Hidden', 1 ], [ 'VeryHidden', 2 ] ]
``````

Non-Excel formats do not support the Very Hidden state. The best way to test if a sheet is visible is to check if the `Hidden` property is logical truth:

``````> wb.Workbook.Sheets.map(function(x) { return [x.name, !x.Hidden] })
[ [ 'Visible', true ], [ 'Hidden', false ], [ 'VeryHidden', false ] ]
``````

#### VBA and Macros

VBA Macros are stored in a special data blob that is exposed in the `vbaraw` property of the workbook object when the `bookVBA` option is `true`. They are supported in `XLSM`, `XLSB`, and `BIFF8 XLS` formats. The supported format writers automatically insert the data blobs if it is present in the workbook and associate with the worksheet names.

Custom Code Names (click to show)

The workbook code name is stored in `wb.Workbook.WBProps.CodeName`. By default, Excel will write `ThisWorkbook` or a translated phrase like `DieseArbeitsmappe`. Worksheet and Chartsheet code names are in the worksheet properties object at `wb.Workbook.Sheets[i].CodeName`. Macrosheets and Dialogsheets are ignored.

The readers and writers preserve the code names, but they have to be manually set when adding a VBA blob to a different workbook.

Macrosheets (click to show)

Older versions of Excel also supported a non-VBA "macrosheet" sheet type that stored automation commands. These are exposed in objects with the `!type` property set to `"macro"`.

Detecting macros in workbooks (click to show)

The `vbaraw` field will only be set if macros are present, so testing is simple:

``````function wb_has_macro(wb/*:workbook*/)/*:boolean*/ {
if(!!wb.vbaraw) return true;
const sheets = wb.SheetNames.map((n) => wb.Sheets[n]);
return sheets.some((ws) => !!ws && ws['!type']=='macro');
}
``````

## Parsing Options

The exported `read` and `readFile` functions accept an options argument:

• Even if `cellNF` is false, formatted text will be generated and saved to `.w`
• In some cases, sheets may be parsed even if `bookSheets` is false.
• Excel aggressively tries to interpret values from CSV and other plain text. This leads to surprising behavior! The `raw` option suppresses value parsing.
• `bookSheets` and `bookProps` combine to give both sets of information
• `Deps` will be an empty object if `bookDeps` is false
• `bookFiles` behavior depends on file type:
• `keys` array (paths in the ZIP) for ZIP-based formats
• `files` hash (mapping paths to objects representing the files) for ZIP
• `cfb` object for formats using CFB containers
• `sheetRows-1` rows will be generated when looking at the JSON object output (since the header row is counted as a row when parsing the data)
• By default all worksheets are parsed. `sheets` restricts based on input type:
• number: zero-based index of worksheet to parse (`0` is first worksheet)
• string: name of worksheet to parse (case insensitive)
• array of numbers and strings to select multiple worksheets.
• `bookVBA` merely exposes the raw VBA CFB object. It does not parse the data. XLSM and XLSB store the VBA CFB object in `xl/vbaProject.bin`. BIFF8 XLS mixes the VBA entries alongside the core Workbook entry, so the library generates a new XLSB-compatible blob from the XLS CFB container.
• `codepage` is applied to BIFF2 - BIFF5 files without `CodePage` records and to CSV files without BOM in `type:"binary"`. BIFF8 XLS always defaults to 1200.
• `PRN` affects parsing of text files without a common delimiter character.
• Currently only XOR encryption is supported. Unsupported error will be thrown for files employing other encryption methods.
• Newer Excel functions are serialized with the `_xlfn.` prefix, hidden from the user. SheetJS will strip `_xlfn.` normally. The `xlfn` option preserves them.
• WTF is mainly for development. By default, the parser will suppress read errors on single worksheets, allowing you to read from the worksheets that do parse properly. Setting `WTF:true` forces those errors to be thrown.

### Input Type

Strings can be interpreted in multiple ways. The `type` parameter for `read` tells the library how to parse the data argument:

### Guessing File Type

Implementation Details (click to show)

Excel and other spreadsheet tools read the first few bytes and apply other heuristics to determine a file type. This enables file type punning: renaming files with the `.xls` extension will tell your computer to use Excel to open the file but Excel will know how to handle it. This library applies similar logic:

DBF files are detected based on the first byte as well as the third and fourth bytes (corresponding to month and day of the file date)

Works for Windows files are detected based on the BOF record with type `0xFF`

Plain text format guessing follows the priority order:

• HTML tags include: `html`, `table`, `head`, `meta`, `script`, `style`, `div`

Why are random text files valid? (click to show)

Excel is extremely aggressive in reading files. Adding an XLS extension to any display text file (where the only characters are ANSI display chars) tricks Excel into thinking that the file is potentially a CSV or TSV file, even if it is only one column! This library attempts to replicate that behavior.

The best approach is to validate the desired worksheet and ensure it has the expected number of rows or columns. Extracting the range is extremely simple:

``````var range = XLSX.utils.decode_range(worksheet['!ref']);
var ncols = range.e.c - range.s.c + 1, nrows = range.e.r - range.s.r + 1;
``````

## Writing Options

The exported `write` and `writeFile` functions accept an options argument:

• `bookSST` is slower and more memory intensive, but has better compatibility with older versions of iOS Numbers
• The raw data is the only thing guaranteed to be saved. Features not described in this README may not be serialized.
• `cellDates` only applies to XLSX output and is not guaranteed to work with third-party readers. Excel itself does not usually write cells with type `d` so non-Excel tools may ignore the data or error in the presence of dates.
• `Props` is an object mirroring the workbook `Props` field. See the table from the Workbook File Properties section.
• if specified, the string from `themeXLSX` will be saved as the primary theme for XLSX/XLSB/XLSM files (to `xl/theme/theme1.xml` in the ZIP)
• Due to a bug in the program, some features like "Text to Columns" will crash Excel on worksheets where error conditions are ignored. The writer will mark files to ignore the error by default. Set `ignoreEC` to `false` to suppress.

### Supported Output Formats

For broad compatibility with third-party tools, this library supports many output formats. The specific file type is controlled with `bookType` option:

• `compression` only applies to formats with ZIP containers.
• Formats that only support a single sheet require a `sheet` option specifying the worksheet. If the string is empty, the first worksheet is used.
• `writeFile` will automatically guess the output file format based on the file extension if `bookType` is not specified. It will choose the first format in the aforementioned table that matches the extension.

### Output Type

The `type` argument for `write` mirrors the `type` argument for `read`:

## Utility Functions

The `sheet_to_*` functions accept a worksheet and an optional options object.

The `*_to_sheet` functions accept a data object and an optional options object.

The examples are based on the following worksheet:

``````XXX| A | B | C | D | E | F | G |
---+---+---+---+---+---+---+---+
1 | S | h | e | e | t | J | S |
2 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
3 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
``````

### Array of Arrays Input

`XLSX.utils.aoa_to_sheet` takes an array of arrays of JS values and returns a worksheet resembling the input data. Numbers, Booleans and Strings are stored as the corresponding styles. Dates are stored as date or numbers. Array holes and explicit `undefined` values are skipped. `null` values may be stubbed. All other values are stored as strings. The function takes an options argument:

Examples (click to show)

To generate the example sheet:

``````var ws = XLSX.utils.aoa_to_sheet([
"SheetJS".split(""),
[1,2,3,4,5,6,7],
[2,3,4,5,6,7,8]
]);
``````

`XLSX.utils.sheet_add_aoa` takes an array of arrays of JS values and updates an existing worksheet object. It follows the same process as `aoa_to_sheet` and accepts an options argument:

`origin` is expected to be one of:

Examples (click to show)

Consider the worksheet:

``````XXX| A | B | C | D | E | F | G |
---+---+---+---+---+---+---+---+
1 | S | h | e | e | t | J | S |
2 | 1 | 2 |   |   | 5 | 6 | 7 |
3 | 2 | 3 |   |   | 6 | 7 | 8 |
4 | 3 | 4 |   |   | 7 | 8 | 9 |
5 | 4 | 5 | 6 | 7 | 8 | 9 | 0 |
``````

This worksheet can be built up in the order `A1:G1, A2:B4, E2:G4, A5:G5`:

``````/* Initial row */
var ws = XLSX.utils.aoa_to_sheet([ "SheetJS".split("") ]);

/* Write data starting at A2 */
XLSX.utils.sheet_add_aoa(ws, [[1,2], [2,3], [3,4]], {origin: "A2"});

/* Write data starting at E2 */
XLSX.utils.sheet_add_aoa(ws, [[5,6,7], [6,7,8], [7,8,9]], {origin:{r:1, c:4}});

/* Append row */
XLSX.utils.sheet_add_aoa(ws, [[4,5,6,7,8,9,0]], {origin: -1});
``````

### Array of Objects Input

`XLSX.utils.json_to_sheet` takes an array of objects and returns a worksheet with automatically-generated "headers" based on the keys of the objects. The default column order is determined by the first appearance of the field using `Object.keys`. The function accepts an options argument:

• All fields from each row will be written. If `header` is an array and it does not contain a particular field, the key will be appended to the array.
• Cell types are deduced from the type of each value. For example, a `Date` object will generate a Date cell, while a string will generate a Text cell.
• Null values will be skipped by default. If `nullError` is true, an error cell corresponding to `#NULL!` will be written to the worksheet.

Examples (click to show)

The original sheet cannot be reproduced using plain objects since JS object keys must be unique. After replacing the second `e` and `S` with `e_1` and `S_1`:

``````var ws = XLSX.utils.json_to_sheet([
{ S:1, h:2, e:3, e_1:4, t:5, J:6, S_1:7 },
{ S:2, h:3, e:4, e_1:5, t:6, J:7, S_1:8 }
``````

Alternatively, the header row can be skipped:

``````var ws = XLSX.utils.json_to_sheet([
{ A:"S", B:"h", C:"e", D:"e", E:"t", F:"J", G:"S" },
{ A: 1,  B: 2,  C: 3,  D: 4,  E: 5,  F: 6,  G: 7  },
{ A: 2,  B: 3,  C: 4,  D: 5,  E: 6,  F: 7,  G: 8  }
``````

`XLSX.utils.sheet_add_json` takes an array of objects and updates an existing worksheet object. It follows the same process as `json_to_sheet` and accepts an options argument:

`origin` is expected to be one of:

Examples (click to show)

Consider the worksheet:

``````XXX| A | B | C | D | E | F | G |
---+---+---+---+---+---+---+---+
1 | S | h | e | e | t | J | S |
2 | 1 | 2 |   |   | 5 | 6 | 7 |
3 | 2 | 3 |   |   | 6 | 7 | 8 |
4 | 3 | 4 |   |   | 7 | 8 | 9 |
5 | 4 | 5 | 6 | 7 | 8 | 9 | 0 |
``````

This worksheet can be built up in the order `A1:G1, A2:B4, E2:G4, A5:G5`:

``````/* Initial row */
var ws = XLSX.utils.json_to_sheet([
{ A: "S", B: "h", C: "e", D: "e", E: "t", F: "J", G: "S" }
], {header: ["A", "B", "C", "D", "E", "F", "G"], skipHeader: true});

/* Write data starting at A2 */
{ A: 1, B: 2 }, { A: 2, B: 3 }, { A: 3, B: 4 }
], {skipHeader: true, origin: "A2"});

/* Write data starting at E2 */
{ A: 5, B: 6, C: 7 }, { A: 6, B: 7, C: 8 }, { A: 7, B: 8, C: 9 }
], {skipHeader: true, origin: { r: 1, c: 4 }, header: [ "A", "B", "C" ]});

/* Append row */
{ A: 4, B: 5, C: 6, D: 7, E: 8, F: 9, G: 0 }
], {header: ["A", "B", "C", "D", "E", "F", "G"], skipHeader: true, origin: -1});
``````

### HTML Table Input

`XLSX.utils.table_to_sheet` takes a table DOM element and returns a worksheet resembling the input table. Numbers are parsed. All other data will be stored as strings.

`XLSX.utils.table_to_book` produces a minimal workbook based on the worksheet.

Both functions accept options arguments:

Examples (click to show)

To generate the example sheet, start with the HTML table:

``````<table id="sheetjs">
<tr><td>S</td><td>h</td><td>e</td><td>e</td><td>t</td><td>J</td><td>S</td></tr>
<tr><td>1</td><td>2</td><td>3</td><td>4</td><td>5</td><td>6</td><td>7</td></tr>
<tr><td>2</td><td>3</td><td>4</td><td>5</td><td>6</td><td>7</td><td>8</td></tr>
</table>
``````

To process the table:

``````var tbl = document.getElementById('sheetjs');
var wb = XLSX.utils.table_to_book(tbl);
``````

Note: `XLSX.read` can handle HTML represented as strings.

`XLSX.utils.sheet_add_dom` takes a table DOM element and updates an existing worksheet object. It follows the same process as `table_to_sheet` and accepts an options argument:

`origin` is expected to be one of:

Examples (click to show)

A small helper function can create gap rows between tables:

``````function create_gap_rows(ws, nrows) {
var ref = XLSX.utils.decode_range(ws["!ref"]);       // get original range
ref.e.r += nrows;                                    // add to ending row
ws["!ref"] = XLSX.utils.encode_range(ref);           // reassign row
}

/* first table */
var ws = XLSX.utils.table_to_sheet(document.getElementById('table1'));
create_gap_rows(ws, 1); // one row gap after first table

/* second table */
XLSX.utils.sheet_add_dom(ws, document.getElementById('table2'), {origin: -1});
create_gap_rows(ws, 3); // three rows gap after second table

/* third table */
XLSX.utils.sheet_add_dom(ws, document.getElementById('table3'), {origin: -1});
``````

### Formulae Output

`XLSX.utils.sheet_to_formulae` generates an array of commands that represent how a person would enter data into an application. Each entry is of the form `A1-cell-address=formula-or-value`. String literals are prefixed with a `'` in accordance with Excel.

Examples (click to show)

For the example sheet:

``````> var o = XLSX.utils.sheet_to_formulae(ws);
> [o[0], o[5], o[10], o[15], o[20]];
[ 'A1=\'S', 'F1=\'J', 'D2=4', 'B3=3', 'G3=8' ]
``````

### Delimiter-Separated Output

As an alternative to the `writeFile` CSV type, `XLSX.utils.sheet_to_csv` also produces CSV output. The function takes an options argument:

• `strip` will remove trailing commas from each line under default `FS/RS`
• `blankrows` must be set to `false` to skip blank lines.
• Fields containing the record or field separator will automatically be wrapped in double quotes; `forceQuotes` forces all cells to be wrapped in quotes.

Examples (click to show)

For the example sheet:

``````> console.log(XLSX.utils.sheet_to_csv(ws));
S,h,e,e,t,J,S
1,2,3,4,5,6,7
2,3,4,5,6,7,8
> console.log(XLSX.utils.sheet_to_csv(ws, {FS:"\t"}));
S    h    e    e    t    J    S
1    2    3    4    5    6    7
2    3    4    5    6    7    8
> console.log(XLSX.utils.sheet_to_csv(ws,{FS:":",RS:"|"}));
S:h:e:e:t:J:S|1:2:3:4:5:6:7|2:3:4:5:6:7:8|
``````

#### UTF-16 Unicode Text

The `txt` output type uses the tab character as the field separator. If the `codepage` library is available (included in full distribution but not core), the output will be encoded in `CP1200` and the BOM will be prepended.

`XLSX.utils.sheet_to_txt` takes the same arguments as `sheet_to_csv`.

### HTML Output

As an alternative to the `writeFile` HTML type, `XLSX.utils.sheet_to_html` also produces HTML output. The function takes an options argument:

Examples (click to show)

For the example sheet:

``````> console.log(XLSX.utils.sheet_to_html(ws));
// ...
``````

### JSON

`XLSX.utils.sheet_to_json` generates different types of JS objects. The function takes an options argument:

• `raw` only affects cells which have a format code (`.z`) field or a formatted text (`.w`) field.
• If `header` is specified, the first row is considered a data row; if `header` is not specified, the first row is the header row and not considered data.
• When `header` is not specified, the conversion will automatically disambiguate header entries by affixing `_` and a count starting at `1`. For example, if three columns have header `foo` the output fields are `foo`, `foo_1`, `foo_2`
• `null` values are returned when `raw` is true but are skipped when false.
• If `defval` is not specified, null and undefined values are skipped normally. If specified, all null and undefined points will be filled with `defval`
• When `header` is `1`, the default is to generate blank rows. `blankrows` must be set to `false` to skip blank rows.
• When `header` is not `1`, the default is to skip blank rows. `blankrows` must be true to generate blank rows

`range` is expected to be one of:

`header` is expected to be one of:

If header is not `1`, the row object will contain the non-enumerable property `__rowNum__` that represents the row of the sheet corresponding to the entry.

Examples (click to show)

For the example sheet:

``````> XLSX.utils.sheet_to_json(ws);
[ { S: 1, h: 2, e: 3, e_1: 4, t: 5, J: 6, S_1: 7 },
{ S: 2, h: 3, e: 4, e_1: 5, t: 6, J: 7, S_1: 8 } ]

[ { A: 'S', B: 'h', C: 'e', D: 'e', E: 't', F: 'J', G: 'S' },
{ A: '1', B: '2', C: '3', D: '4', E: '5', F: '6', G: '7' },
{ A: '2', B: '3', C: '4', D: '5', E: '6', F: '7', G: '8' } ]

[ { '6': 'J', '9': 'S', A: 'S', E: 'h', I: 'e', O: 'e', U: 't' },
{ '6': '6', '9': '7', A: '1', E: '2', I: '3', O: '4', U: '5' },
{ '6': '7', '9': '8', A: '2', E: '3', I: '4', O: '5', U: '6' } ]

[ [ 'S', 'h', 'e', 'e', 't', 'J', 'S' ],
[ '1', '2', '3', '4', '5', '6', '7' ],
[ '2', '3', '4', '5', '6', '7', '8' ] ]
``````

Example showing the effect of `raw`:

``````> ws['A2'].w = "3";                          // set A2 formatted string value

> XLSX.utils.sheet_to_json(ws, {header:1, raw:false});
[ [ 'S', 'h', 'e', 'e', 't', 'J', 'S' ],
[ '3', '2', '3', '4', '5', '6', '7' ],     // <-- A2 uses the formatted string
[ '2', '3', '4', '5', '6', '7', '8' ] ]

[ [ 'S', 'h', 'e', 'e', 't', 'J', 'S' ],
[ 1, 2, 3, 4, 5, 6, 7 ],                   // <-- A2 uses the raw value
[ 2, 3, 4, 5, 6, 7, 8 ] ]
``````

## File Formats

Despite the library name `xlsx`, it supports numerous spreadsheet file formats:

Features not supported by a given file format will not be written. Formats with range limits will be silently truncated:

Excel 2003 SpreadsheetML range limits are governed by the version of Excel and are not enforced by the writer.

### Excel 2007+ XML (XLSX/XLSM)

(click to show)

XLSX and XLSM files are ZIP containers containing a series of XML files in accordance with the Open Packaging Conventions (OPC). The XLSM format, almost identical to XLSX, is used for files containing macros.

The format is standardized in ECMA-376 and later in ISO/IEC 29500. Excel does not follow the specification, and there are additional documents discussing how Excel deviates from the specification.

### Excel 2.0-95 (BIFF2/BIFF3/BIFF4/BIFF5)

(click to show)

BIFF 2/3 XLS are single-sheet streams of binary records. Excel 4 introduced the concept of a workbook (`XLW` files) but also had single-sheet `XLS` format. The structure is largely similar to the Lotus 1-2-3 file formats. BIFF5/8/12 extended the format in various ways but largely stuck to the same record format.

There is no official specification for any of these formats. Excel 95 can write files in these formats, so record lengths and fields were determined by writing in all of the supported formats and comparing files. Excel 2016 can generate BIFF5 files, enabling a full suite of file tests starting from XLSX or BIFF2.

### Excel 97-2004 Binary (BIFF8)

(click to show)

BIFF8 exclusively uses the Compound File Binary container format, splitting some content into streams within the file. At its core, it still uses an extended version of the binary record format from older versions of BIFF.

The `MS-XLS` specification covers the basics of the file format, and other specifications expand on serialization of features like properties.

### Excel 2003-2004 (SpreadsheetML)

(click to show)

Predating XLSX, SpreadsheetML files are simple XML files. There is no official and comprehensive specification, although MS has released documentation on the format. Since Excel 2016 can generate SpreadsheetML files, mapping features is pretty straightforward.

### Excel 2007+ Binary (XLSB, BIFF12)

(click to show)

Introduced in parallel with XLSX, the XLSB format combines the BIFF architecture with the content separation and ZIP container of XLSX. For the most part nodes in an XLSX sub-file can be mapped to XLSB records in a corresponding sub-file.

The `MS-XLSB` specification covers the basics of the file format, and other specifications expand on serialization of features like properties.

### Delimiter-Separated Values (CSV/TXT)

(click to show)

Excel CSV deviates from RFC4180 in a number of important ways. The generated CSV files should generally work in Excel although they may not work in RFC4180 compatible readers. The parser should generally understand Excel CSV. The writer proactively generates cells for formulae if values are unavailable.

Excel TXT uses tab as the delimiter and code page 1200.

Notes:

• Like in Excel, files starting with `0x49 0x44 ("ID")` are treated as Symbolic Link files. Unlike Excel, if the file does not have a valid SYLK header, it will be proactively reinterpreted as CSV. There are some files with semicolon delimiter that align with a valid SYLK file. For the broadest compatibility, all cells with the value of `ID` are automatically wrapped in double-quotes.

### Other Workbook Formats

(click to show)

Support for other formats is generally far XLS/XLSB/XLSX support, due in large part to a lack of publicly available documentation. Test files were produced in the respective apps and compared to their XLS exports to determine structure. The main focus is data extraction.

#### Lotus 1-2-3 (WKS/WK1/WK2/WK3/WK4/123)

(click to show)

The Lotus formats consist of binary records similar to the BIFF structure. Lotus did release a specification decades ago covering the original WK1 format. Other features were deduced by producing files and comparing to Excel support.

Generated WK1 worksheets are compatible with Lotus 1-2-3 R2 and Excel 5.0.

Generated WK3 workbooks are compatible with Lotus 1-2-3 R9 and Excel 5.0.

#### Quattro Pro (WQ1/WQ2/WB1/WB2/WB3/QPW)

(click to show)

The Quattro Pro formats use binary records in the same way as BIFF and Lotus. Some of the newer formats (namely WB3 and QPW) use a CFB enclosure just like BIFF8 XLS.

#### Works for DOS / Windows Spreadsheet (WKS/XLR)

(click to show)

All versions of Works were limited to a single worksheet.

Works for DOS 1.x - 3.x and Works for Windows 2.x extends the Lotus WKS format with additional record types.

Works for Windows 3.x - 5.x uses the same format and WKS extension. The BOF record has type `FF`

Works for Windows 6.x - 9.x use the XLR format. XLR is nearly identical to BIFF8 XLS: it uses the CFB container with a Workbook stream. Works 9 saves the exact Workbook stream for the XLR and the 97-2003 XLS export. Works 6 XLS includes two empty worksheets but the main worksheet has an identical encoding. XLR also includes a `WksSSWorkBook` stream similar to Lotus FM3/FMT files.

#### OpenDocument Spreadsheet (ODS/FODS)

(click to show)

ODS is an XML-in-ZIP format akin to XLSX while FODS is an XML format akin to SpreadsheetML. Both are detailed in the OASIS standard, but tools like LO/OO add undocumented extensions. The parsers and writers do not implement the full standard, instead focusing on parts necessary to extract and store raw data.

#### Uniform Office Spreadsheet (UOS1/2)

(click to show)

UOS is a very similar format, and it comes in 2 varieties corresponding to ODS and FODS respectively. For the most part, the difference between the formats is in the names of tags and attributes.

### Other Single-Worksheet Formats

Many older formats supported only one worksheet:

#### dBASE and Visual FoxPro (DBF)

(click to show)

DBF is really a typed table format: each column can only hold one data type and each record omits type information. The parser generates a header row and inserts records starting at the second row of the worksheet. The writer makes files compatible with Visual FoxPro extensions.

Multi-file extensions like external memos and tables are currently unsupported, limited by the general ability to read arbitrary files in the web browser. The reader understands DBF Level 7 extensions like DATETIME.

#### Symbolic Link (SYLK)

(click to show)

There is no real documentation. All knowledge was gathered by saving files in various versions of Excel to deduce the meaning of fields. Notes:

• Plain formulae are stored in the RC form.
• Column widths are rounded to integral characters.

#### Lotus Formatted Text (PRN)

(click to show)

There is no real documentation, and in fact Excel treats PRN as an output-only file format. Nevertheless we can guess the column widths and reverse-engineer the original layout. Excel's 240 character width limitation is not enforced.

#### Data Interchange Format (DIF)

(click to show)

There is no unified definition. Visicalc DIF differs from Lotus DIF, and both differ from Excel DIF. Where ambiguous, the parser/writer follows the expected behavior from Excel. In particular, Excel extends DIF in incompatible ways:

• Since Excel automatically converts numbers-as-strings to numbers, numeric string constants are converted to formulae: `"0.3" -> "=""0.3""`
• DIF technically expects numeric cells to hold the raw numeric data, but Excel permits formatted numbers (including dates)
• DIF technically has no support for formulae, but Excel will automatically convert plain formulae. Array formulae are not preserved.

#### HTML

(click to show)

Excel HTML worksheets include special metadata encoded in styles. For example, `mso-number-format` is a localized string containing the number format. Despite the metadata the output is valid HTML, although it does accept bare `&` symbols.

The writer adds type metadata to the TD elements via the `t` tag. The parser looks for those tags and overrides the default interpretation. For example, text like `<td>12345</td>` will be parsed as numbers but `<td t="s">12345</td>` will be parsed as text.

#### Rich Text Format (RTF)

(click to show)

Excel RTF worksheets are stored in clipboard when copying cells or ranges from a worksheet. The supported codes are a subset of the Word RTF support.

#### Ethercalc Record Format (ETH)

(click to show)

Ethercalc is an open source web spreadsheet powered by a record format reminiscent of SYLK wrapped in a MIME multi-part message.

## Testing

### Node

(click to show)

`make test` will run the node-based tests. By default it runs tests on files in every supported format. To test a specific file type, set `FMTS` to the format you want to test. Feature-specific tests are available with `make test_misc`

``````\$ make test_misc   # run core tests
\$ make test        # run full tests
\$ make test_xls    # only use the XLS test files
\$ make test_xlsx   # only use the XLSX test files
\$ make test_xlsb   # only use the XLSB test files
\$ make test_xml    # only use the XML test files
\$ make test_ods    # only use the ODS test files
``````

To enable all errors, set the environment variable `WTF=1`:

``````\$ make test        # run full tests
\$ WTF=1 make test  # enable all error messages
``````

`flow` and `eslint` checks are available:

``````\$ make lint        # eslint checks
\$ make flow        # make lint + Flow checking
\$ make tslint      # check TS definitions
``````

### Browser

(click to show)

The core in-browser tests are available at `tests/index.html` within this repo. Start a local server and navigate to that directory to run the tests. `make ctestserv` will start a server on port 8000.

`make ctest` will generate the browser fixtures. To add more files, edit the `tests/fixtures.lst` file and add the paths.

To run the full in-browser tests, clone the repo for `oss.sheetjs.com` and replace the `xlsx.js` file (then open a browser window and go to `stress.html`):

``````\$ cp xlsx.js ../SheetJS.github.io
\$ cd ../SheetJS.github.io
\$ simplehttpserver # or "python -mSimpleHTTPServer" or "serve"
\$ open -a Chromium.app http://localhost:8000/stress.html
``````

### Tested Environments

(click to show)

• NodeJS `0.8`, `0.10`, `0.12`, `4.x`, `5.x`, `6.x`, `7.x`, `8.x`
• IE 6/7/8/9/10/11 (IE 6-9 require shims)
• Chrome 24+ (including Android 4.0+)
• Safari 6+ (iOS and Desktop)
• Edge 13+, FF 18+, and Opera 12+

Tests utilize the mocha testing framework.

The test suite also includes tests for various time zones. To change the timezone locally, set the TZ environment variable:

``````\$ env TZ="Asia/Kolkata" WTF=1 make test_misc
``````

### Test Files

Test files are housed in another repo.

Running `make init` will refresh the `test_files` submodule and get the files. Note that this requires `svn`, `git`, `hg` and other commands that may not be available. If `make init` fails, please download the latest version of the test files snapshot from the repo

Latest Snapshot (click to show)

(download and unzip to the `test_files` subdirectory)

## Contributing

Due to the precarious nature of the Open Specifications Promise, it is very important to ensure code is cleanroom. Contribution Notes

File organization (click to show)

At a high level, the final script is a concatenation of the individual files in the `bits` folder. Running `make` should reproduce the final output on all platforms. The README is similarly split into bits in the `docbits` folder.

Folders:

After cloning the repo, running `make help` will display a list of commands.

### OSX/Linux

(click to show)

The `xlsx.js` file is constructed from the files in the `bits` subdirectory. The build script (run `make`) will concatenate the individual bits to produce the script. Before submitting a contribution, ensure that running make will produce the `xlsx.js` file exactly. The simplest way to test is to add the script:

``````\$ git add xlsx.js
\$ make clean
\$ make
\$ git diff xlsx.js
``````

To produce the dist files, run `make dist`. The dist files are updated in each version release and should not be committed between versions.

### Windows

(click to show)

The included `make.cmd` script will build `xlsx.js` from the `bits` directory. Building is as simple as:

``````> make
``````

To prepare development environment:

``````> make init
``````

The full list of commands available in Windows are displayed in `make help`:

``````make init -- install deps and global modules
make lint -- run eslint linter
make test -- run mocha test suite
make misc -- run smaller test suite
make book -- rebuild README and summary
make help -- display this message
``````

As explained in Test Files, on Windows the release ZIP file must be downloaded and extracted. If Bash on Windows is available, it is possible to run the OSX/Linux workflow. The following steps prepares the environment:

``````# Install support programs for the build and test commands
sudo apt-get install make git subversion mercurial

# Install nodejs and NPM within the WSL
wget -qO- https://deb.nodesource.com/setup_8.x | sudo bash
sudo apt-get install nodejs

# Install dev dependencies
sudo npm install -g mocha voc blanket xlsjs
``````

### Tests

(click to show)

The `test_misc` target (`make test_misc` on Linux/OSX / `make misc` on Windows) runs the targeted feature tests. It should take 5-10 seconds to perform feature tests without testing against the entire test battery. New features should be accompanied with tests for the relevant file formats and features.

For tests involving the read side, an appropriate feature test would involve reading an existing file and checking the resulting workbook object. If a parameter is involved, files should be read with different values to verify that the feature is working as expected.

For tests involving a new write feature which can already be parsed, appropriate feature tests would involve writing a workbook with the feature and then opening and verifying that the feature is preserved.

For tests involving a new write feature without an existing read ability, please add a feature test to the kitchen sink `tests/write.js`.

Please consult the attached LICENSE file for details. All rights not explicitly granted by the Apache 2.0 License are reserved by the Original Author.

## References

OSP-covered Specifications (click to show)

• `MS-CFB`: Compound File Binary File Format
• `MS-CTXLS`: Excel Custom Toolbar Binary File Format
• `MS-EXSPXML3`: Excel Calculation Version 2 Web Service XML Schema
• `MS-ODATA`: Open Data Protocol (OData)
• `MS-ODRAW`: Office Drawing Binary File Format
• `MS-ODRAWXML`: Office Drawing Extensions to Office Open XML Structure
• `MS-OE376`: Office Implementation Information for ECMA-376 Standards Support
• `MS-OFFCRYPTO`: Office Document Cryptography Structure
• `MS-OI29500`: Office Implementation Information for ISO/IEC 29500 Standards Support
• `MS-OLEDS`: Object Linking and Embedding (OLE) Data Structures
• `MS-OLEPS`: Object Linking and Embedding (OLE) Property Set Data Structures
• `MS-OODF3`: Office Implementation Information for ODF 1.2 Standards Support
• `MS-OSHARED`: Office Common Data Types and Objects Structures
• `MS-OVBA`: Office VBA File Format Structure
• `MS-XLDM`: Spreadsheet Data Model File Format
• `MS-XLS`: Excel Binary File Format (.xls) Structure Specification
• `MS-XLSB`: Excel (.xlsb) Binary File Format
• `MS-XLSX`: Excel (.xlsx) Extensions to the Office Open XML SpreadsheetML File Format
• `XLS`: Microsoft Office Excel 97-2007 Binary File Format Specification
• `RTF`: Rich Text Format
• ISO/IEC 29500:2012(E) "Information technology — Document description and processing languages — Office Open XML File Formats"
• Open Document Format for Office Applications Version 1.2 (29 September 2011)
• Worksheet File Format (From Lotus) December 1984

Author: SheetJS
Source Code: https://github.com/SheetJS/sheetjs

1596754901

## Testing Microservices Applications

The shift towards microservices and modular applications makes testing more important and more challenging at the same time. You have to make sure that the microservices running in containers perform well and as intended, but you can no longer rely on conventional testing strategies to get the job done.

This is where new testing approaches are needed. Testing your microservices applications require the right approach, a suitable set of tools, and immense attention to details. This article will guide you through the process of testing your microservices and talk about the challenges you will have to overcome along the way. Let’s get started, shall we?

## A Brave New World

Traditionally, testing a monolith application meant configuring a test environment and setting up all of the application components in a way that matched the production environment. It took time to set up the testing environment, and there were a lot of complexities around the process.

Testing also requires the application to run in full. It is not possible to test monolith apps on a per-component basis, mainly because there is usually a base code that ties everything together, and the app is designed to run as a complete app to work properly.

Microservices running in containers offer one particular advantage: universal compatibility. You don’t have to match the testing environment with the deployment architecture exactly, and you can get away with testing individual components rather than the full app in some situations.

Of course, you will have to embrace the new cloud-native approach across the pipeline. Rather than creating critical dependencies between microservices, you need to treat each one as a semi-independent module.

The only monolith or centralized portion of the application is the database, but this too is an easy challenge to overcome. As long as you have a persistent database running on your test environment, you can perform tests at any time.

Keep in mind that there are additional things to focus on when testing microservices.

• Microservices rely on network communications to talk to each other, so network reliability and requirements must be part of the testing.
• Automation and infrastructure elements are now added as codes, and you have to make sure that they also run properly when microservices are pushed through the pipeline
• While containerization is universal, you still have to pay attention to specific dependencies and create a testing strategy that allows for those dependencies to be included

Test containers are the method of choice for many developers. Unlike monolith apps, which lets you use stubs and mocks for testing, microservices need to be tested in test containers. Many CI/CD pipelines actually integrate production microservices as part of the testing process.

## Contract Testing as an Approach

As mentioned before, there are many ways to test microservices effectively, but the one approach that developers now use reliably is contract testing. Loosely coupled microservices can be tested in an effective and efficient way using contract testing, mainly because this testing approach focuses on contracts; in other words, it focuses on how components or microservices communicate with each other.

Syntax and semantics construct how components communicate with each other. By defining syntax and semantics in a standardized way and testing microservices based on their ability to generate the right message formats and meet behavioral expectations, you can rest assured knowing that the microservices will behave as intended when deployed.

## Ways to Test Microservices

It is easy to fall into the trap of making testing microservices complicated, but there are ways to avoid this problem. Testing microservices doesn’t have to be complicated at all when you have the right strategy in place.

There are several ways to test microservices too, including:

• Unit testing: Which allows developers to test microservices in a granular way. It doesn’t limit testing to individual microservices, but rather allows developers to take a more granular approach such as testing individual features or runtimes.
• Integration testing: Which handles the testing of microservices in an interactive way. Microservices still need to work with each other when they are deployed, and integration testing is a key process in making sure that they do.
• End-to-end testing: Which⁠—as the name suggests⁠—tests microservices as a complete app. This type of testing enables the testing of features, UI, communications, and other components that construct the app.

What’s important to note is the fact that these testing approaches allow for asynchronous testing. After all, asynchronous development is what makes developing microservices very appealing in the first place. By allowing for asynchronous testing, you can also make sure that components or microservices can be updated independently to one another.

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