postcss#

• Type: Object | Function
• Default:

const defaultOptions = {
  postcssOptions: {
    plugins: [require('autoprefixer')({ flexbox: 'no-2009' })],
    sourceMap: rsbuildConfig.output.sourceMap.css,
  },
};

Rsbuild integrates PostCSS by default, you can configure postcss-loader through tools.postcss.

Note that, for performance, Rsbuild uses postcss-load-config to load external config files and merges them with the default config.

Function Type#

When the value is a Function, the internal default config is passed as the first parameter, and the config object can be modified directly without returning, or an object can be returned as the final result; the second parameter is a set of tool functions for modifying the postcss-loader config.

For example, you need to add a PostCSS plugin on the basis of the original plugin, and push a new plugin to the postcssOptions.plugins array:

export default {
  tools: {
    postcss: (opts) => {
      opts.postcssOptions.plugins.push(require('postcss-px-to-viewport'));
    },
  },
};

When you need to pass parameters to the PostCSS plugin, you can pass them in by function parameters:

export default {
  tools: {
    postcss: (opts) => {
      const viewportPlugin = require('postcss-px-to-viewport')({
        viewportWidth: 375,
      });
      opts.postcssOptions.plugins.push(viewportPlugin);
    },
  },
};

tools.postcss can return a config object and completely replace the default config:

export default {
  tools: {
    postcss: () => {
      return {
        postcssOptions: {
          plugins: [require('postcss-px-to-viewport')],
        },
      };
    },
  },
};

Object Type#

When this value is an Object, it is merged with the default config via Object.assign. Note that Object.assign is a shallow copy and will completely overwrite the built-in presets or plugins array, please use it with caution.

export default {
  tools: {
    postcss: {
      // Because `Object.assign` is used, the default postcssOptions will be overwritten.
      postcssOptions: {
        plugins: [require('postcss-px-to-viewport')],
      },
    },
  },
};

Util Functions#

addPlugins#

• Type: (plugins: PostCSSPlugin | PostCSSPlugin[]) => void

For adding additional PostCSS plugins, You can pass in a single PostCSS plugin, or an array of PostCSS plugins.

export default {
  tools: {
    postcss: (config, { addPlugins }) => {
      // Add a PostCSS Plugin
      addPlugins(require('postcss-preset-env'));
      // Add multiple PostCSS Plugins
      addPlugins([require('postcss-preset-env'), require('postcss-import')]);
    },
  },
};