esbuild-wasm

What is esbuild-wasm?

The esbuild-wasm package is a WebAssembly-based version of the esbuild bundler and minifier. It provides extremely fast build times and is designed to be used in environments where native binaries cannot be executed, such as in browsers or some serverless platforms. It supports transforming, bundling, and minifying JavaScript and TypeScript files.

What are esbuild-wasm's main functionalities?

Bundling JavaScript

This code initializes esbuild-wasm and bundles a JavaScript file, outputting a single bundled file. It demonstrates how to set up and execute a basic bundling process.

const esbuild = require('esbuild-wasm');
esbuild.initialize({ worker: true, wasmURL: '/path/to/esbuild.wasm' }).then(() => {
  esbuild.build({
    entryPoints: ['input.js'],
    bundle: true,
    outfile: 'output.js'
  }).catch(() => process.exit(1));
});

Minifying CSS

This example shows how to use esbuild-wasm to minify a CSS file. It sets up the esbuild environment and performs minification, outputting the minified CSS.

const esbuild = require('esbuild-wasm');
esbuild.initialize({ worker: true, wasmURL: '/path/to/esbuild.wasm' }).then(() => {
  esbuild.build({
    entryPoints: ['input.css'],
    minify: true,
    outfile: 'output.css'
  }).catch(() => process.exit(1));
});

Transpiling TypeScript

This code snippet demonstrates how to transpile TypeScript into JavaScript using esbuild-wasm. It includes setting up the environment, specifying the loader for TypeScript files, and bundling the output.

const esbuild = require('esbuild-wasm');
esbuild.initialize({ worker: true, wasmURL: '/path/to/esbuild.wasm' }).then(() => {
  esbuild.build({
    entryPoints: ['input.ts'],
    loader: { '.ts': 'ts' },
    outfile: 'output.js',
    bundle: true
  }).catch(() => process.exit(1));
});

Other packages similar to esbuild-wasm

webpack

Webpack is a popular JavaScript module bundler with a vast ecosystem of plugins. It offers more configuration options and plugins compared to esbuild-wasm but is generally slower in terms of build speed.

rollup

Rollup is another module bundler that focuses on producing efficient bundles. It is known for its tree-shaking capabilities, which are similar to esbuild-wasm, but Rollup typically has slower build times and less efficient minification.

parcel

Parcel is a web application bundler that requires zero configuration for quick setup. It provides fast build times similar to esbuild-wasm and supports various file types natively, but it might not reach the same speed for larger projects.

README

esbuild

This is the cross-platform WebAssembly binary for esbuild, a JavaScript bundler and minifier. See https://github.com/evanw/esbuild and the JavaScript API documentation for details.

Changelog

0.24.0

This release deliberately contains backwards-incompatible changes. To avoid automatically picking up releases like this, you should either be pinning the exact version of esbuild in your package.json file (recommended) or be using a version range syntax that only accepts patch upgrades such as ^0.23.0 or ~0.23.0. See npm's documentation about semver for more information.

• Drop support for older platforms (#3902)

  This release drops support for the following operating system:

  • macOS 10.15 Catalina

  This is because the Go programming language dropped support for this operating system version in Go 1.23, and this release updates esbuild from Go 1.22 to Go 1.23. Go 1.23 now requires macOS 11 Big Sur or later.

  Note that this only affects the binary esbuild executables that are published to the esbuild npm package. It's still possible to compile esbuild's source code for these older operating systems. If you need to, you can compile esbuild for yourself using an older version of the Go compiler (before Go version 1.23). That might look something like this:

  git clone https://github.com/evanw/esbuild.git
  cd esbuild
  go build ./cmd/esbuild
  ./esbuild --version
  

• Fix class field decorators in TypeScript if useDefineForClassFields is false (#3913)

  Setting the useDefineForClassFields flag to false in tsconfig.json means class fields use the legacy TypeScript behavior instead of the standard JavaScript behavior. Specifically they use assign semantics instead of define semantics (e.g. setters are triggered) and fields without an initializer are not initialized at all. However, when this legacy behavior is combined with standard JavaScript decorators, TypeScript switches to always initializing all fields, even those without initializers. Previously esbuild incorrectly continued to omit field initializers for this edge case. These field initializers in this case should now be emitted starting with this release.

• Avoid incorrect cycle warning with tsconfig.json multiple inheritance (#3898)

  TypeScript 5.0 introduced multiple inheritance for tsconfig.json files where extends can be an array of file paths. Previously esbuild would incorrectly treat files encountered more than once when processing separate subtrees of the multiple inheritance hierarchy as an inheritance cycle. With this release, tsconfig.json files containing this edge case should work correctly without generating a warning.

• Handle Yarn Plug'n'Play stack overflow with tsconfig.json (#3915)

  Previously a tsconfig.json file that extends another file in a package with an exports map could cause a stack overflow when Yarn's Plug'n'Play resolution was active. This edge case should work now starting with this release.

• Work around more issues with Deno 1.31+ (#3917)

  This version of Deno broke the stdin and stdout properties on command objects for inherited streams, which matters when you run esbuild's Deno module as the entry point (i.e. when import.meta.main is true). Previously esbuild would crash in Deno 1.31+ if you ran esbuild like that. This should be fixed starting with this release.

  This fix was contributed by @Joshix-1.