@gatsbyjs/react-refresh-webpack-plugin

React Refresh Webpack Plugin

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

Prerequisites

First and foremost, this plugin is not 100% stable. We're working towards a stable v1 release, and we've been testing the plugin quite extensively; but since it is still pretty young, there might still be some unknown edge cases.

There are no breaking changes planned for the v1 release, but they might still happen if we hit some significant road blockers.

Also, ensure that you are using the minimum supported versions of the plugin's peer dependencies - older versions unfortunately do not contain code to orchestrate "Fast Refresh", and thus cannot be made compatible.

Dependency	Minimum	Best
react	16.9.0	16.13.0+
react-dom	16.9.0	16.13.0+
react-reconciler	0.22.0	0.25.0+
webpack	4.0.0 (for 0.3.x) 4.43.0 (for 0.4.x+)	4.43.0+

You only need react-dom if you're rendering to the DOM.

You only need to check for react-reconciler if you use custom reconcilers like react-three-fiber. You should check their package.json to make sure they use a compatible version instead of installing react-reconciler yourself. If the reconcilers are not compatible, please create an issue at their repository.

Installation

With all prerequisites met, you can install the plugin with one of the commands below:

# 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

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

The plugin depends on a package from the React team - react-refresh, so you will have to install and configure it separately as demonstrated in the Usage section.

TypeScript

TypeScript support is available out-of-the-box for those who use webpack.config.ts :tada:!

For that you will have to install type-fest as a development peer dependency with one of the commands below:

# if you prefer npm
npm install -D type-fest

# if you prefer yarn
yarn add -D type-fest

# if you prefer pnpm
pnpm add -D type-fest

Usage

The most basic setup to enable "Fast Refresh" is to update your webpack.config.js (or .ts) as follows:

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

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

module.exports = {
  // It is suggested to run both `react-refresh/babel` and the plugin in the `development` mode only,
  // even though both of them have optimisations in place to do nothing in the `production` mode.
  // If you would like to override Webpack's defaults for modes, you can also use the `none` mode -
  // you then will need to set `forceEnable: true` in the plugin's options.
  mode: isDevelopment ? 'development' : 'production',
  module: {
    rules: [
      // ... other rules
      {
        test: /\.[jt]sx?$/,
        exclude: /node_modules/,
        use: [
          // ... other loaders
          {
            loader: require.resolve('babel-loader'),
            options: {
              // ... other options
              plugins: [
                // ... other plugins
                isDevelopment && require.resolve('react-refresh/babel'),
              ].filter(Boolean),
            },
          },
        ],
      },
    ],
  },
  plugins: [
    // ... other plugins
    isDevelopment && new webpack.HotModuleReplacementPlugin(),
    isDevelopment && new ReactRefreshWebpackPlugin(),
  ].filter(Boolean),
  // ... other configuration options
};

You might want to further tweak the configuration to accommodate your setup:

• isDevelopment

  In this example we've shown the simple way of splitting up development and production builds with the NODE_ENV environment variable. It will default to true (i.e. development mode) when NODE_ENV is not available from the environment.

  In practice though, you might want to wire this up differently, like using a function config or using multiple configuration files.

• webpack.HotModuleReplacementPlugin

  If you use webpack-dev-server or webpack-plugin-serve, you can set devServer.hot/devServer.hotOnly and hmr to true respectively, instead of adding the HMR plugin to your plugin list.

Note: 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.

Integration Support for Overlay

Officially, webpack-dev-server, webpack-hot-middleware and webpack-plugin-serve are supported out of the box - you just have to set the overlay.sockIntegration option to match what you're using.

For each of the integrations listed above, you can also take a look at the corresponding sample projects for a better understanding of how things should be wired up.

API

Please refer to the API docs for all available options.

FAQs and Troubleshooting

Please refer to the Troubleshooting guide for FAQs and resolutions to common issues.

License

This project is licensed under the terms of the MIT License.

Related Work

• Initial Implementation by @maisano