#source.include

• Type: Rspack.RuleSetCondition

Specify additional JavaScript files that need to be compiled by SWC.

#Default value

By default, Rsbuild's built-in swc-loader compiles the following files:

• TypeScript and JSX files in any directory, matching file extensions .ts, .tsx, .jsx, .mts, .cts.
• JavaScript files that are not in the node_modules directory, matching file extensions .js, .mjs, .cjs.

The default value of source.include can be expressed as:

const defaultInclude = [
  { not: /[\\/]node_modules[\\/]/ },
  /\.(?:ts|tsx|jsx|mts|cts)$/,
];

#Usage

Through the source.include configuration, you can specify directories or modules that need to be compiled by Rsbuild. The usage of source.include is consistent with Rule.include in Rspack, which supports passing in strings or regular expressions to match the module path.

For example:

import path from 'node:path';

export default {
  source: {
    include: [path.resolve(__dirname, '../other-dir')],
  },
};

#Compile npm packages

A typical usage scenario is to compile npm packages under node_modules, because some third-party dependencies have ESNext syntax, which may cause them to fail to run on older browsers. You can solve this problem by using this configuration to specify the dependencies that need to be compiled.

Take query-string as an example, you can add the following configuration:

import path from 'node:path';

export default {
  source: {
    include: [
      // Method 1:
      // Match by regular expression
      // All paths containing `node_modules/query-string/` will be matched
      /node_modules[\\/]query-string[\\/]/,
      // Method 2:
      // First get the path of the module by require.resolve
      // Then pass path.dirname to point to the corresponding directory
      path.dirname(require.resolve('query-string')),
    ],
  },
};

The above two methods match the absolute paths of files using "path prefixes" and "regular expressions" respectively. It is worth noting that all referenced modules in the project will be matched. Therefore, you should avoid using overly loose values for matching to prevent compilation performance issues or compilation errors.

#Compile sub dependencies

When you compile an npm package via source.include, Rsbuild will only compile the matching module by default, not the Sub Dependencies of the module.

Take query-string for example, it depends on the decode-uri-component package, which also has ESNext code, so you need to add the decode-uri-component package to source.include as well.

export default {
  source: {
    include: [
      /node_modules[\\/]query-string[\\/]/,
      /node_modules[\\/]decode-uri-component[\\/]/,
    ],
  },
};

#Matching symlink

If you match a module that is symlinked to the current project, then you need to match the real path of the module, not the symlinked path.

For example, if you symlink the packages/foo path in Monorepo to the node_modules/foo path of the current project, you need to match the packages/foo path, not the node_modules/foo path.

#Compile node_modules

In general, source.include should not be used to compile the entire node_modules directory. For example, the following configuration is not recommended:

export default {
  source: {
    include: [/[\\/]node_modules[\\/]/],
  },
};

This is because most of the npm packages in node_modules are already compiled, and it is usually unnecessary to recompile them. Compiling the entire node_modules will increase compilation time and may cause unexpected errors in certain npm packages, such as core-js, which may result in runtime exceptions after compilation.

If you are willing to accept the increase in compilation time, you can use the following configuration to compile all JavaScript files but exclude `core-js':

export default {
  source: {
    include: [{ not: /[\\/]core-js[\\/]/ }],
  },
};