react-native-esbuild

The fastest bundler for React Native.

Features

• Fast – ~10-50x faster depending on project
• Tree shaking – Smaller bundles means faster apps
• Compatible – Drop-in replacement for metro
• Configurable – Support for custom transformers and env variables

Sponsoring

If this library helped you, please consider sponsoring.

Installation

yarn add react-native-esbuild esbuild

Configuration

react-native CLI plugin

Make sure react-native.config.js exists in the root of your project, and create one if not. Add this library to the commands section like this:

// react-native.config.js
const { commands } = require('react-native-esbuild');

module.exports = {
  commands,
};

Optional: Esbuild settings

If you want to customize the esbuild configuration, for example by adding your own plugins you may do so with the createEsbuildCommands function. This example adds babel transformation for reanimated support:

// react-native.config.js
const { createEsbuildCommands, babelPlugin } = require('react-native-esbuild');

// See https://esbuild.github.io/api/#simple-options
const commands = createEsbuildCommands((config) => ({
  ...config,
  plugins: config.plugins.concat(
    babelPlugin({
      filter:
        /(node_modules\/react-native-reanimated|src\/my-reanimated-components)\/.+\.[tj]sx?$/,
      config: {
        filename: config.outfile,
      },
    })
  ),
}));

module.exports = {
  commands,
};

Optional: Use esbuild for development

1. Open package.json in your editor and locate scripts section.
2. Edit start script to be react-native esbuild-start.
3. Prevent metro from starting automatically by appending --no-packager to the ios/android scripts.

{
  "scripts": {
    "android": "react-native run-android --no-packager",
    "ios": "react-native run-ios --no-packager",
    "start": "react-native esbuild-start"
  }
}

Optional: Build production app with esbuild

Android

Set project.ext.react.bundleCommand to esbuild-bundle in android/app/build.gradle:

// android/app/build.gradle
project.ext.react = [
    enableHermes: false,
    bundleCommand: "esbuild-bundle",
]

iOS

1. Open your iOS project in Xcode manually or with xed ios
2. Select the Build Phases tab in your project settings.
3. Expand the Bundle React Native code and images section and add export BUNDLE_COMMAND=esbuild-bundle so it looks like this:

set -e

export BUNDLE_COMMAND=esbuild-bundle
export NODE_BINARY=node
../node_modules/react-native/scripts/react-native-xcode.sh

Usage

This library aims to be a plug-in replacement for the metro equivalent commands with the esbuild- prefix.

react-native esbuild-start

Argument	Description	Default
--port	Port to listen for http requests	8081
--host	Host to listen for http requests	127.0.0.1
--projectRoot	Path to a custom project root.	None
--reset-cache	Removes cached files.	N/A

react-native esbuild-bundle

Argument	Description	Default
--entry-file	Path to the root JS file, either absolute or relative to JS root	index.js
--platform	Either ios or android	ios
--dev	If false, warnings are disabled and the bundle is minified	true
--minify	Allows overriding whether bundle is minified otherwise determined by dev value.	Opposite of dev
--bundle-output	File name where to store the resulting bundle.	None
--sourcemap-output	File name where to store the sourcemap file for resulting bundle.	None
--assets-dest	Directory name where to store assets referenced in the bundle.	None
--reset-cache	Removes cached files.	N/A

Troubleshooting

Flow syntax errors such as Expected "from" but found "{"

Esbuild doesn't natively support flow so such syntax needs to be stripped with a plugin. By default any node module with react-native in their name will be stripped from flow, but it's also possible to do this on your own source code using the babelPlugin mentioned in the Configuration section, but at the cost of performance.

react-native main field ignored

A few rare packages using the react-native field for ESM maps, will not be correctly resolved by esbuild. To remedy this use the bundled esmCustomMainFieldResolverPlugin:

// react-native.config.js
const {
  createEsbuildCommands,
  esmCustomMainFieldResolverPlugin,
} = require('react-native-esbuild');

const commands = createEsbuildCommands(({ plugins, ...rest }) => ({
  ...rest,
  plugins: plugins.concat(esmCustomMainFieldResolverPlugin()),
}));

module.exports = {
  commands,
};

Limitations

Hermes engine

Hermes doesn't support crucial ES6 features like block level scoping (let/const) and the team doesn't seem to want to merge this feature mentioning it being a too big of a change without having good enough reasons to add it.

HMR/Fast Refresh

Esbuild doesn't support Fast Refresh or Hot Module Replacement, but this library supports live reload instead.

License

MIT © Joel Arvidsson 2022-