#resolve.mainFields

• Type: string[]
• Version: >= 1.5.9

Controls the priority of fields in a package.json used to locate a package's entry file. It is the ordered list of package.json fields Rspack will try when resolving an npm package's entry point.

#Default values

• If output.target is 'web', 'web-worker', or not specified, the default value is ["browser", "module", "main"].
• If output.target is 'node', the default value is ["module", "main"].

#Basic example

The value of resolve.mainFields overrides the default value of Rsbuild:

export default {
  resolve: {
    mainFields: ['custom', 'module', 'main'],
  },
};

#Multi-environments

Configure different mainFields for different environments:

export default {
  environments: {
    web: {
      resolve: {
        mainFields: ['custom', 'browser', 'module', 'main'],
      },
    },
    node: {
      resolve: {
        mainFields: ['custom', 'module', 'main'],
      },
    },
  },
};