Camaro: A High Performance XML to JSON Converter

Camaro: A High Performance XML to JSON Converter

Camaro is an utility to transform XML to JSON, using Node.js binding to native XML parser pugixml, one of the fastest XML parser around (Uses bindings to pugixml, a fast C++ XML parser.)


camaro is an utility to transform XML to JSON, using Node.js binding to native XML parser pugixml, one of the fastest XML parser around.

metal Features

  • Transform XML to JSON.
  • Only take properties that you're interested in.
  • Output is a ready to use JS object.
  • For those that need a complete document parser, checkout my other project @tuananh/sax-parser - a pretty fast native module, XML-compliant SAX parser for Node.js.
  • Written in C++ and compiled down to WebAssembly so no re-compilation needed.
  • No need to build binary whenever a new Node version released.
  • Work on all major platforms (OS X, Linux and Windows). See Travis CI and AppVeyor build status for details.
  • AWS Lambda friendly (or serverless in general).
  • It's pretty fast on large XML strings.
  • We're using pugixml underneath. It's one of the fastest XML parser around.
  • Scale well with multi-core processor by use of worker_threads pool (Node >= 12).
  • Pretty print XML.

fire Benchmark

300 KB XML file 100 KB XML file

60 KB XML file 7 KB XML file

XML file is an actual XML response from Expedia API. I just delete some nodes to change its size for benchmarking.

For complete benchmark, see benchmark/

  • Please note that this is an unfair game for camaro because it only transform those fields specified in template. The whole reason of me creating this is because most of the time, I'm just interested in some of the data in the whole XML mess.
  • I may expose another method to transform the whole XML tree so that the benchmark will better reflect the real performance.
  • construction Performance on small XML strings will probably be worse than pure JavaScript implementation. If your use cases consist of small XML strings only, you probably don't need this.
  • Some other libraries that I used to use for benchmark like rapidx2j or xml2json no longer works on Node 14 so I remove them from the benchmark.



yarn add camaro
## npm install camaro


You can use our custom template format powered by XPath.

We also introduce some custom syntax such as:

  • if a path start with #, that means it's a constant. E.g: #1234 will return 1234
  • if a path is empty, return blank
  • Some string manipulation functions which are not availble in XPath 1.0 such as lower-case, upper-case, title-case, camel-case, snake-case, string-join or raw. Eventually, I'm hoping to add all XPath 2.0 functions but these are all that I need for now. PRs welcome.

The rest are pretty much vanilla XPath 1.0.

For complete API documentation, please see

Additional examples can be found in the examples folder at

const { transform, prettyPrint } = require('camaro')

const xml = `
        <player jerseyNumber="10">
            <name>wayne rooney</name>
        <player jerseyNumber="7">
            <name>cristiano ronaldo</name>
        <player jerseyNumber="7">
            <name>eric cantona</name>

 * the template can be an object or an array depends on what output you want the XML to be transformed to.
 * ['players/player', {name, ...}] means that: Get all the nodes with this XPath expression `players/player`.
 *      - the first param is the XPath path to get all the XML nodes.
 *      - the second param is a string or an object that describe the shape of the array element and how to get it.
 * For each of those XML node
 *      - call the XPath function `title-case` on field `name` and assign it to `name` field of the output.
 *      - get the attribute `jerseyNumber` from XML node player
 *      - get the `yearOfBirth` attribute from `yearOfBirth` and cast it to number.
 *      - cast `isRetired` to true if its string value equals to "true", and false otherwise.

const template = ['players/player', {
    name: 'title-case(name)',
    jerseyNumber: '@jerseyNumber',
    yearOfBirth: 'number(yearOfBirth)',
    isRetired: 'boolean(isRetired = "true")'

;(async function () {
    const result = await transform(xml, template)

    const prettyStr = await prettyPrint(xml, { indentSize: 4})

Output of transform()

        name: 'Wayne Rooney',
        jerseyNumber: 10,
        yearOfBirth: 1985,
        isRetired: false,
        name: 'Cristiano Ronaldo',
        jerseyNumber: 7,
        yearOfBirth: 1985,
        isRetired: false,
        name: 'Eric Cantona',
        jerseyNumber: 7,
        yearOfBirth: 1966,
        isRetired: true,

And output of prettyPrint()

    <player jerseyNumber="10">
        <name>Wayne Rooney</name>
    <player jerseyNumber="7">
        <name>Cristiano Ronaldo</name>
    <player jerseyNumber="7">
        <name>Eric Cantona</name>

Similar projects

  • cruftless: I personally find this project very fascinating. Its template engine is more powerful than camaro's XPath-based perhaps. You should check it out.

json xml camaro programming developer

Bootstrap 5 Complete Course with Examples

Bootstrap 5 Tutorial - Bootstrap 5 Crash Course for Beginners

Nest.JS Tutorial for Beginners

Hello Vue 3: A First Look at Vue 3 and the Composition API

Building a simple Applications with Vue 3

Deno Crash Course: Explore Deno and Create a full REST API with Deno

How to Build a Real-time Chat App with Deno and WebSockets

Convert HTML to Markdown Online

HTML entity encoder decoder Online

How long does it take to develop/build an app?

This article covers A-Z about the mobile and web app development process and answers your question on how long does it take to develop/build an app.

Developer Career Path: To Become a Team Lead or Stay a Developer?

For a developer, becoming a team leader can be a trap or open up opportunities for creating software. Two years ago, when I was a developer, ... by Oleg Sklyarov, Fullstack Developer at Skyeng company

Tracking a Developer’s Journey From Documentation Visit

Measuring website activity provides only half the story. See how to best track the developer's journey and what funnel stages makes sense for API-first products

Offshore Software Development - Best Practices

To make the most out of the benefits of offshore software development, you should understand the crucial factors that affect offshore development.

Understanding JSON in JavaScript - Learn JSON With Practical Examples

JSON stands for JavaScript Object Notation. The JSON syntax is derived from JavaScript object notation syntax, but the JSON format is text only. the code that generates JSON data can be written in any programming language, not only JavaScript.