Configure Rspack#

Rsbuild supports directly modifying the Rspack configuration object, and also supports modifying the built-in Rspack configuration of Rsbuild through the bundler-chain.

Modify Rspack Config#

You can use the tools.rspack option of Rsbuild to modify the Rspack configuration object. Please refer to the tools.rspack documentation for complete usage.

export default {
  tools: {
    rspack: (config, { env }) => {
      if (env === 'development') {
        config.devtool = 'cheap-module-eval-source-map';
      }
      return config;
    },
  },
};

Use Bundler Chain#

Bundler chain is a subset of webpack chain, which contains part of the webpack chain API that you can use to modify both Rspack and webpack configuration.

Configurations modified via bundler chain will work on both Rspack and webpack builds. Note that the bundler chain only supports modifying the configuration of the non-differentiated parts of Rspack and webpack. For example, modifying the devtool configuration option (Rspack and webpack have the same devtool property value type), or adding an Rspack-compatible webpack plugin.

Compared to directly modifying the Rspack configuration object, bundler-chain not only supports chain calls but also allows modification of built-in rules or plugins based on their IDs.

tools.bundlerChain#

Rsbuild provides the tools.bundlerChain configuration option to modify the bundler chain.

The value of tools.bundlerChain is a Function type that accepts two parameters:

• The first parameter is the bundler-chain instance, which can be used to modify the default bundler configuration.
• The second parameter is utils that includes env, isProd, CHAIN_ID, and more.

Here's a basic example:

export default {
  tools: {
    bundlerChain: (chain, { env }) => {
      if (env === 'development') {
        chain.devtool('cheap-module-eval-source-map');
      }
    },
  },
};

Basics#

Before using the bundler chain to modify the Rspack configuration, it is recommended to familiarize yourself with some basics.

How the Bundler Chain Locates Objects Quickly#

In short, the bundler chain requires users to set a unique ID for each rule, loader, plugin, and minimizer. With this ID, you can easily find the desired object from deeply nested objects.

Rsbuild exports all internally defined IDs through the CHAIN_ID object, so you can quickly locate the loader or plugin you want to modify using these exported IDs, without the need for complex traversal in the Rspack configuration object.

For example, you can remove the built-in HTML plugin using CHAIN_ID.PLUGIN.HTML:

export default {
  tools: {
    bundlerChain: (chain, { CHAIN_ID }) => {
      //
      chain.plugins.delete(CHAIN_ID.PLUGIN.HTML);
    },
  },
};

Types of Bundler Chain IDs#

The CHAIN_ID object contains various IDs, which correspond to the following configurations:

Examples#

Configure loader#

Here are examples of adding, modifying, and deleting Rspack loaders.

export default {
  tools: {
    bundlerChain: (chain, { CHAIN_ID }) => {
      // Add loader
      chain.module
        .rule('md')
        .test(/\.md$/)
        .use('md-loader')
        .loader('md-loader');

      // Modify loader
      chain.module
        .rule(CHAIN_ID.RULE.JS)
        .use(CHAIN_ID.USE.BABEL)
        .tap((options) => {
          options.plugins.push('babel-plugin-abc');
          return options;
        });

      // Delete loader
      chain.module.rule(CHAIN_ID.RULE.JS).uses.delete(CHAIN_ID.USE.BABEL);
    },
  },
};

Configure Plugin#

Here are examples of adding, modifying, and deleting Rspack plugins.

export default {
  tools: {
    bundlerChain: (chain, { bundler, CHAIN_ID }) => {
      // Add plugin
      chain.plugin('custom-define').use(bundler.DefinePlugin, [
        {
          'process.env': {
            NODE_ENV: JSON.stringify(process.env.NODE_ENV),
          },
        },
      ]);

      // Modify plugin
      chain.plugin(CHAIN_ID.PLUGIN.HMR).tap((options) => {
        options[0].fullBuildTimeout = 200;
        return options;
      });

      // Delete plugin
      chain.plugins.delete(CHAIN_ID.PLUGIN.HMR);
    },
  },
};

Modify based on environment#

In the tools.bundlerChain function, you can access various environment identifiers in the second parameter, such as development/production build, SSR build, Web Worker build, to achieve configuration modifications for different environments.

export default {
  tools: {
    bundlerChain: (chain, { env, isProd, target, isServer, isWebWorker }) => {
      if (utils.env === 'development' || utils.env === 'test') {
        // ...
      }
      if (utils.isProd) {
        // ...
      }
      if (utils.target === 'node') {
        // ...
      }
      if (utils.isServer) {
        // ...
      }
      if (utils.isWebWorker) {
        // ...
      }
    },
  },
};

The above are some common configuration examples. For the complete bundler-chain API, please refer to the webpack-chain documentation.