React Refresh Webpack Plugin

An EXPERIMENTAL Webpack plugin to enable "Fast Refresh" (also previously known as Hot Reloading) for React components.

Installation

First - this plugin is not 100% stable. It works pretty reliably, and we have been testing it for some time, but there are still edge cases yet to be discovered. Please DO NOT use it if you cannot afford to face breaking changes in the future.

# if you prefer npm
npm install -D @pmmmwh/react-refresh-webpack-plugin react-refresh

# if you prefer yarn
yarn add -D @pmmmwh/react-refresh-webpack-plugin react-refresh

Usage

First, apply the plugin in your Webpack configuration as follows:

webpack.config.js

const ReactRefreshWebpackPlugin = require('@pmmmwh/react-refresh-webpack-plugin');
// ... your other imports

// You can tie this to whatever mechanisms you are using to detect a development environment.
// For example, as shown here, is to tie that to `NODE_ENV` -
// Then if you run `NODE_ENV=production webpack`, the constant will be set to false.
const isDevelopment = process.env.NODE_ENV !== 'production';

module.exports = {
  // It is suggested to run the plugin in development mode only
  // If you are an advanced user and would like to setup Webpack yourselves,
  // you can also use the `none` mode,
  // but you will need to set `forceEnable: true` in the plugin options.
  mode: isDevelopment ? 'development' : 'production',
  // ... other configurations
  plugins: [
    // ... other plugins
    // You could also keep the plugin in your production config,
    // It will simply do nothing.
    isDevelopment && new ReactRefreshWebpackPlugin(),
  ].filter(Boolean),
};

Then, update your Babel configuration. This can either be done in your Webpack config (via options of babel-loader), or in the form of a .babelrc/babel.config.js.

webpack.config.js (if you choose to inline the config)

const isDevelopment = process.env.NODE_ENV !== 'production';

module.exports = {
  // DO NOT apply the plugin in production mode!
  mode: isDevelopment ? 'development' : 'production',
  module: {
    rules: [
      // ... other rules
      {
        // for TypeScript, change the following to "\.[jt]sx?"
        test: /\.jsx?$/,
        exclude: /node_modules/,
        use: [
          // ... other loaders
          {
            loader: require.resolve('babel-loader'),
            options: {
              // ... other options
              // DO NOT apply the Babel plugin in production mode!
              plugins: [isDevelopment && require.resolve('react-refresh/babel')].filter(Boolean),
            },
          },
        ],
      },
    ],
  },
};

.babelrc.js (if you choose to extract the config)

module.exports = (api) => {
  // This caches the Babel config by environment.
  api.cache.using(() => process.env.NODE_ENV);
  return {
    // ... other options
    plugins: [
      // ... other plugins
      // Applies the react-refresh Babel plugin on non-production modes only
      !api.env('production') && 'react-refresh/babel',
    ].filter(Boolean),
  };
};

More sample projects for common Webpack development setups are available in the examples directory.

Note 1: If you use webpack.config.ts, please also install type-fest as a peer dependency.

Note 2: If you are using TypeScript (instead of Babel) as a transpiler, you will still need to use babel-loader to process your source code. Check out this sample project on how to set this up.

Caveats

• Class components will be re-mounted on hot update. See this comment for more background on why this is the case.
• Unnamed components will fallback to full refresh. See this comment for more info and why this is generally a bad idea.

Polyfill for Older Browsers

If you need to develop on IE11, you will need to polyfill the DOM URL API. This can be done by adding the following before any of your code in the main entry (either one is fine):

Using url-polyfill

import 'url-polyfill';

Using core-js

import 'core-js/features/url';
import 'core-js/features/url-search-params';

Using react-app-polyfill

import 'react-app-polyfill/ie11';
import 'react-app-polyfill/stable';

Options

This plugin accepts a few options that are specifically targeted for advanced users.

options.forceEnable

Type: boolean Default: false

Enables the plugin forcefully. Useful if you want to use the plugin in production, or if you are using Webpack's none mode without NODE_ENV, for example.

options.overlay

Type: boolean | ErrorOverlayOptions Default: undefined

Modifies how the error overlay integration works in the plugin.

• If options.overlay is not provided or is true, the plugin will use the bundled error overlay interation.

• If options.overlay is false, it will disable the error overlay integration.

• If an ErrorOverlayOptions object is provided: (NOTE: This is an advanced option that exists mostly for tools like create-react-app or Next.js)

  • An optional module property could be defined. If it is not defined, the bundled error overlay will be used. If it is false, it will disable the error overlay integration. If defined, it should reference a JS file that exports at least two functions with footprints as follows:

    function handleRuntimeError(error: Error) {}
    function clearRuntimeErrors() {}

  • An optional entry property could be defined, which should also reference a JS file that contains code needed to set up your custom error overlay integration. If it is not defined, the bundled error overlay entry will be used. If it is false, no error overlay entry will be injected. It expects the module file to export two more functions:

    function showCompileError(webpackErrorMessage: string) {}
    function clearCompileErrors() {}

    Note that webpackErrorMessage is ANSI encoded, so you will need logic to parse it.

  • An example configuration:

    const options = {
      overlay: {
        entry: 'some-webpack-entry-file',
        module: 'some-error-overlay-module',
      },
    };

options.overlay.sockHost

Type: string Default: window.location.hostname

Set this if you are running webpack on a host other than window.location.hostname. This will be used by the error overlay module, and is available for webpack-dev-server only.

options.overlay.sockIntegration

Type: wds, whm, wps, false or string Default: wds

This controls how the error overlay connects to the sockets provided by several Webpack hot reload integrations.

• If you use webpack-dev-server, you don't need to set this as it defaults to wds.
• If you use webpack-hot-middleware, you should set this to whm.
• If you use webpack-plugin-serve, you should set this to wps.
• If you use anything else, or if you want to customize the socket handling yourself, you will have to provide a path to a module that will accept a message handler function and initializes the socket connection. See the sockets directory for sample implementations.

options.overlay.sockPort

Type: number Default: window.location.port

Set this if you are running webpack on a port other than window.location.port. This will be used by the error overlay module, and is available for webpack-dev-server only.

options.overlay.sockPath

Type: string Default: /sockjs-node

Set this if you are running webpack on a custom path. This will be used by the error overlay module, and is available for webpack-dev-server only.

options.overlay.useLegacyWDSSockets

Type: boolean Default: false

Set this to true if you are using a webpack-dev-server version prior to 3.8 as it requires a custom SockJS implementation. If you use this feature, you will also need to install sockjs-client as a peer dependency.

Related Work

• Initial Implementation by @maisano