#resolve

Options for module resolution.

#resolve.aliasStrategy resolve.aliasStrategy

Control the priority between the resolve.alias option and the paths option in tsconfig.json.

#resolve.alias resolve.alias

Set the alias for the module path, which is used to simplify the import path or redirect the module reference, similar to the resolve.alias config of Rspack.

For TypeScript projects, you only need to configure compilerOptions.paths in the tsconfig.json file. Rslib will automatically recognize it, so there is no need to configure the resolve.alias option separately.

It is worth noting that in bundle mode, both resolve.alias and output.externals can be used to set aliases, but they differ in the following ways:

• resolve.alias is used to replace the target module with another module, which will be bundled into the output.

  For example, if you want to replace lodash with lodash-es when bundling a package, you can configure it as follows:

  rslib.config.ts

  export default {
    // ...
    resolve: {
      alias: {
        lodash: 'lodash-es',
      },
    },
  };

  Now, all lodash imports in the source code will be mapped to lodash-es and bundled into the output.

• output.externals is used to handle alias mapping for externalized modules. Externalized modules are not included in the bundle; instead, they are imported from external sources at runtime.

  For example, if you want to replace externalized modules react and react-dom with preact/compat in the bundle, you can configure it as follows:

  rslib.config.ts

  export default {
    // ...
    output: {
      externals: {
        react: 'preact/compat',
        'react-dom': 'preact/compat',
      },
    },
  };

  Now, the code import { useState } from 'react' will be replaced with import { useState } from 'preact/compat'.

#resolve.dedupe resolve.dedupe

Force Rsbuild to resolve the specified packages from project root, which is useful for deduplicating packages and reducing the bundle size.

#resolve.extensions resolve.extensions

Automatically resolve file extensions when importing modules. This means you can import files without explicitly writing their extensions.