#HotModuleReplacementPlugin

Enables hot module replacement (HMR).

new rspack.HotModuleReplacementPlugin();

#Example

Enabling HMR is straightforward and in most cases no options are necessary.

Note that HMR can not be used in production build. You can use process.env.NODE_ENV to determine if it is a development environment.

import { rspack } from '@rspack/core';
const isDev = process.env.NODE_ENV === 'development';

export default {
  plugins: [isDev && new rspack.HotModuleReplacementPlugin()],
};

#Runtime API

When you register the HotModuleReplacementPlugin plugin, Rspack will inject HMR related runtime APIs, such as module.hot and import.meta.webpackHot.

See HMR API for more details.

#React Fast Refresh

To enable Fast Refresh in React projects, you also need to use the @rspack/plugin-react-refresh plugin.

See React - Fast Refresh for more details.

#Preact Fast Refresh

To enable Fast Refresh in Preact projects, you also need to use the @rspack/plugin-preact-refresh plugin.

See Preact - Fast Refresh for more details.