Debbie Clay

Debbie Clay


Fast JavaScript bundling with esbuild

Modular programming is a software design technique whereby a program’s various functions are subdivided into code modules that are developed separately. Modern programming relies heavily on modularity, which is why you need a module bundler to merge all separate files into a single one.

There are a few bundlers available in the JavaScript community, such as WebPack, Rollup, and Parcel. However, these are not fast enough because they are built with JavaScript, which, as well all know, leaves much to be desired in terms of performance. Fortunately, there is a new bundler built with Go that works faster than other bundlers.

In this guide, we’ll explore esbuild, a JavaScript bundler and minifier that packages JS code for distribution on the web. We’ll examine how it’s able to work so fast and discuss why you should keep an eye on this tool in 2020 and beyond.

What is esbuild, and why?

This is a JavaScript bundler and minifier. It packages up JavaScript code for distribution on the web.

Why build another JavaScript build tool? The current build tools for the web are at least an order of magnitude slower than they should be. I’m hoping that this project serves as an “existence proof” that our JavaScript tooling can be much, much faster.

Comparing esbuild to other bundlers (Benchmark)

esbuild fully parallelizes parsing, printing, and source map generation. All these features combine to make esbuild extremely fast. That said, to help you choose the best bundler for your next JavaScript project, let’s compare esbuild to other tools on the market.

My main benchmark approximates a large codebase by duplicating the three.js library 10 times and building a single bundle from scratch, without any caches. For this benchmark, esbuild is 10-100x faster than the other JavaScript bundlers I tested (Webpack, Rollup, Parcel, and FuseBox). The benchmark can be run with make bench-three.

Benchmark Comparison of JavaScript Bundlers

Each time reported is the best of three runs. I’m running esbuild with --bundle --minify --sourcemap. I used the rollup-plugin-terser plugin because rollup itself doesn’t support minification. Webpack uses --mode=production --devtool=sourcemap. Parcel uses the default options. FuseBox is configured with useSingleBundle: true. Absolute speed is based on the total line count including comments and blank lines, which is currently 547,441. The tests were done on a 6-core 2019 MacBook Pro with 16gb of RAM.

The result of the benchmarking is mind-blowing: esbuild is 10 to 100 times faster than other bundlers.

By the way, you can run this benchmark on your machine and see it for yourself. Install the Go language toolchain and run the following command:

make bench-three

Why is it fast?

Several reasons:

  • It’s written in Go, a language that compiles to native code
  • Parsing, printing, and source map generation are all fully parallelized
  • Everything is done in very few passes without expensive data transformations
  • Code is written with speed in mind, and tries to avoid unnecessary allocations


Currently supported:

  • CommonJS modules
  • ES6 modules
  • Bundling with static binding of ES6 modules using --bundle
  • Full minification with --minify (whitespace, identifiers, and mangling)
  • Full source map support when --sourcemap is enabled
  • JSX-to-JavaScript conversion for .jsx files
  • Compile-time identifier substitutions via --define
  • Path substitution using the browser field in package.json
  • Automatic detection of baseUrl in tsconfig.json

This is a hobby project that I wrote over the 2019-2020 winter break. I believe that it’s relatively complete and functional. However, it’s brand new code and probably has a lot of bugs. It also hasn’t yet been used in production by anyone. Use at your own risk.

Also keep in mind that this doesn’t have complete support for lowering modern language syntax to earlier language versions. Right now only class fields and the nullish coalescing operator are lowered.

I don’t personally want to run a large open source project, so I’m not looking for contributions at this time.

Is esbuild production-ready?

There’s no disputing this bundler’s speed. But is it production-ready?

For now, esbuild is a small open-source project; it’s developed and maintained by one man. This is largely by design. Per the author: “I don’t personally want to run a large open-source project, so I’m not looking for contributions at this time.”

Although this will inevitably slow the development of the tool, it’s already a great bundler with robust support for common JS modules, JSX-to-JavaScript conversion, etc. However, it has yet to be used in production; doing so right now would be risky and would likely unearth some bugs.

That said, esbuild has tremendous potential to streamline the traditionally sluggish task of bundling modules in JavaScript, and it’s worth trying out in your next project.


The executable can be built using make, assuming you have the Go language toolchain installed. Prebuilt binaries are currently available on npm under separate packages:

npm install -g esbuild-linux-64   # for Linux
npm install -g esbuild-darwin-64  # for macOS
npm install -g esbuild-windows-64 # for Windows
npm install -g esbuild-wasm       # for all other platforms

This adds a command called esbuild.


The command-line interface takes a list of entry points and produces one bundle file per entry point. Here are the available options:

  esbuild [options] [entry points]

  --name=...            The name of the module
  --bundle              Bundle all dependencies into the output files
  --outfile=...         The output file (for one entry point)
  --outdir=...          The output directory (for multiple entry points)
  --sourcemap           Emit a source map
  --error-limit=...     Maximum error count or 0 to disable (default 10)
  --target=...          Language target (default esnext)

  --minify              Sets all --minify-* flags
  --minify-whitespace   Remove whitespace
  --minify-identifiers  Shorten identifiers
  --minify-syntax       Use equivalent but shorter syntax

  --define:K=V          Substitute K with V while parsing
  --jsx-factory=...     What to use instead of React.createElement
  --jsx-fragment=...    What to use instead of React.Fragment

  --trace=...           Write a CPU trace to this file
  --cpuprofile=...      Write a CPU profile to this file

  # Produces dist/entry_point.js and dist/
  esbuild --bundle entry_point.js --outdir=dist --minify --sourcemap

Using with React

To use esbuild with React:

  • Make sure all JSX syntax is put in .jsx files instead of .js files because esbuild uses the file extension to determine what syntax to parse.

  • If you’re using TypeScript, run tsc first to convert .tsx files into either .jsx or .js files.

  • If you’re using esbuild to bundle React yourself instead of including it with a <script> tag in your HTML, you’ll need to pass '--define:process.env.NODE_ENV="development"' or '--define:process.env.NODE_ENV="production"' to esbuild on the command line.

  • If you’re using Preact instead of React, you’ll also need to pass --jsx-factory=preact.h --jsx-fragment=preact.Fragment to esbuild on the command line.

For example, if you have a file called example.jsx with the following contents:

import * as React from 'react'
import * as ReactDOM from 'react-dom'

  <h1>Hello, world!</h1>,

Use this for a development build:

esbuild example.jsx --bundle '--define:process.env.NODE_ENV="development"' --outfile=out.js

Use this for a production build:

esbuild example.jsx --bundle '--define:process.env.NODE_ENV="production"' --minify --outfile=out.js


If nothing else, esbuild is proof that our current JavaScript build tools are not fast enough. Given that the gap between esbuild and other bundlers is so wide in terms of performance, I hope this tool will help improve build tools in general across the JS ecosystem.

#javascript #web-development

What is GEEK

Buddha Community

Fast JavaScript bundling with esbuild

Rahul Jangid


What is JavaScript - Stackfindover - Blog

Who invented JavaScript, how it works, as we have given information about Programming language in our previous article ( What is PHP ), but today we will talk about what is JavaScript, why JavaScript is used The Answers to all such questions and much other information about JavaScript, you are going to get here today. Hope this information will work for you.

Who invented JavaScript?

JavaScript language was invented by Brendan Eich in 1995. JavaScript is inspired by Java Programming Language. The first name of JavaScript was Mocha which was named by Marc Andreessen, Marc Andreessen is the founder of Netscape and in the same year Mocha was renamed LiveScript, and later in December 1995, it was renamed JavaScript which is still in trend.

What is JavaScript?

JavaScript is a client-side scripting language used with HTML (Hypertext Markup Language). JavaScript is an Interpreted / Oriented language called JS in programming language JavaScript code can be run on any normal web browser. To run the code of JavaScript, we have to enable JavaScript of Web Browser. But some web browsers already have JavaScript enabled.

Today almost all websites are using it as web technology, mind is that there is maximum scope in JavaScript in the coming time, so if you want to become a programmer, then you can be very beneficial to learn JavaScript.

JavaScript Hello World Program

In JavaScript, ‘document.write‘ is used to represent a string on a browser.

<script type="text/javascript">
	document.write("Hello World!");

How to comment JavaScript code?

  • For single line comment in JavaScript we have to use // (double slashes)
  • For multiple line comments we have to use / * – – * /
<script type="text/javascript">

//single line comment

/* document.write("Hello"); */


Advantages and Disadvantages of JavaScript

#javascript #javascript code #javascript hello world #what is javascript #who invented javascript

Hire Dedicated JavaScript Developers -Hire JavaScript Developers

It is said that a digital resource a business has must be interactive in nature, so the website or the business app should be interactive. How do you make the app interactive? With the use of JavaScript.

Does your business need an interactive website or app?

Hire Dedicated JavaScript Developer from WebClues Infotech as the developer we offer is highly skilled and expert in what they do. Our developers are collaborative in nature and work with complete transparency with the customers.

The technology used to develop the overall app by the developers from WebClues Infotech is at par with the latest available technology.

Get your business app with JavaScript

For more inquiry click here

Book Free Interview:

#hire dedicated javascript developers #hire javascript developers #top javascript developers for hire #hire javascript developer #hire a freelancer for javascript developer #hire the best javascript developers

Niraj Kafle


The essential JavaScript concepts that you should understand

As a JavaScript developer of any level, you need to understand its foundational concepts and some of the new ideas that help us developing code. In this article, we are going to review 16 basic concepts. So without further ado, let’s get to it.

#javascript-interview #javascript-development #javascript-fundamental #javascript #javascript-tips

Ajay Kapoor


JS Development Company India | JavaScript Development Services

PixelCrayons: Our JavaScript web development service offers you a feature-packed & dynamic web application that effectively caters to your business challenges and provide you the best RoI. Our JavaScript web development company works on all major frameworks & libraries like Angular, React, Nodejs, Vue.js, to name a few.

With 15+ years of domain expertise, we have successfully delivered 13800+ projects and have successfully garnered 6800+ happy customers with 97%+ client retention rate.

Looking for professional JavaScript web app development services? We provide custom JavaScript development services applying latest version frameworks and libraries to propel businesses to the next level. Our well-defined and manageable JS development processes are balanced between cost, time and quality along with clear communication.

Our JavaScript development companies offers you strict NDA, 100% money back guarantee and agile/DevOps approach.

#javascript development company #javascript development services #javascript web development #javascript development #javascript web development services #javascript web development company

Santosh J


JavaScript compound assignment operators

JavaScript is unarguablly one of the most common things you’ll learn when you start programming for the web. Here’s a small post on JavaScript compound assignment operators and how we use them.

The compound assignment operators consist of a binary operator and the simple assignment operator.

The binary operators, work with two operands. For example a+b where + is the operator and the a, b are operands. Simple assignment operator is used to assign values to a variable(s).

It’s quite common to modify values stored in variables. To make this process a little quicker, we use compound assignment operators.

They are:

  • +=
  • -+
  • *=
  • /=

You can also check my video tutorial compound assignment operators.

Let’s consider an example. Suppose price = 5 and we want to add ten more to it.

var price = 5;
price = price + 10;

We added ten to price. Look at the repetitive price variable. We could easily use a compound += to reduce this. We do this instead.

price += 5;

Awesome. Isn’t it? What’s the value of price now? Practice and comment below. If you don’t know how to practice check these lessons.

Lets bring down the price by 5 again and display it.
We use console.log command to display what is stored in the variable. It is very help for debugging.
Debugging let’s you find errors or bugs in your code. More on this later.

price -= 5;

Lets multiply price and show it.

price *=5;

and finally we will divide it.

price /=5;

If you have any doubts, comment below.

#javascript #javascript compound assignment operators #javascript binary operators #javascript simple assignment operator #doers javascript