output.cssModules#

• Type:

type CSSModules = {
  auto?:
    | boolean
    | RegExp
    | ((
        resourcePath: string,
        resourceQuery: string,
        resourceFragment: string,
      ) => boolean);
  localIdentName?: string;
  exportLocalsConvention?: CSSModulesLocalsConvention;
};

For custom CSS Modules configuration.

The CSS Modules feature of Rsbuild is based on the modules option of css-loader. You can refer to css-loader - modules to learn more.

cssModules.auto#

The auto configuration option allows CSS Modules to be automatically enabled based on their filenames.

• Type:

type Auto =
  | boolean
  | RegExp
  | ((
      resourcePath: string,
      resourceQuery: string,
      resourceFragment: string,
    ) => boolean);

• Default: true

Type description:

• true: enable CSS Modules for all files matching /\.module\.\w+$/i.test(filename) regexp.
• false: disable CSS Modules.
• RegExp: enable CSS Modules for all files matching /RegExp/i.test(filename) regexp.
• function: enable CSS Modules for files based on the filename satisfying your filter function check.

export default {
  output: {
    cssModules: {
      auto: (resource) => {
        return resource.includes('.module.') || resource.includes('shared/');
      },
    },
  },
};

cssModules.exportLocalsConvention#

Style of exported class names.

• Type:

type CSSModulesLocalsConvention =
  | 'asIs'
  | 'camelCase'
  | 'camelCaseOnly'
  | 'dashes'
  | 'dashesOnly';

• Default: 'camelCase'

Type description:

• asIs Class names will be exported as is.
• camelCase Class names will be camelized, the original class name will not to be removed from the locals.
• camelCaseOnly Class names will be camelized, the original class name will be removed from the locals.
• dashes Only dashes in class names will be camelized.
• dashesOnly Dashes in class names will be camelized, the original class name will be removed from the locals.

export default {
  output: {
    cssModules: {
      exportLocalsConvention: 'camelCaseOnly',
    },
  },
};

cssModules.localIdentName#

• Type: string
• Default:

// isProd indicates that the production build
const localIdentName = isProd
  ? '[local]-[hash:base64:6]'
  : '[path][name]__[local]-[hash:base64:6]';

Sets the format of the class names generated by CSS Modules after compilation.

Default Value#

localIdentName has different default values in development and production.

In a production, Rsbuild will generate shorter class names to reduce the bundle size.

import styles from './index.module.scss';

// In development, the value is `src-index-module__header-[hash]`
// In production, the value is `header-[hash]`
console.log(styles.header);

Template String#

You can use the following template strings in localIdentName:

• [name] - the basename of the asset.
• [local] - original class.
• [hash] - the hash of the string.
• [folder] - the folder relative path.
• [path] - the relative path.
• [file] - filename and path.
• [ext] - extension with leading dot.
• [hash:<hashDigest>:<hashDigestLength>]: hash with hash settings.

Example#

Set localIdentName to other value:

export default {
  output: {
    cssModules: {
      localIdentName: '[hash:base64:4]',
    },
  },
};

cssModules.exportGlobals#

• Type: boolean
• Default: false

Allows exporting names from global class names, so you can use them via import.

Example#

Set the exportGlobals to true:

export default {
  output: {
    cssModules: {
      exportGlobals: true,
    },
  },
};

Use :global() in CSS Modules:

:global(.blue) {
  color: blue;
}

.red {
  color: red;
}

Then you can import the class name wrapped with :global():

import styles from './style.module.css';

console.log(styles.blue); // 'blue'
console.log(styles.red); // 'red-[hash]'