Custom Webpack Config

Flareact allows you to customize the Webpack config for your worker and client builds.

To modify the Webpack config, define a flareact.config.js file in the root of your project:

module.exports = {
  webpack: (config, { dev, isWorker, defaultLoaders, webpack }) => {
    // Note: we provide webpack above so you should not `require` it
    // Perform customizations to webpack config
    config.plugins.push(new webpack.IgnorePlugin(/\/__tests__\//));

    // Important: return the modified config
    return config;

The webpack function is executed twice, once for the worker and once for the client. This allows you to distinguish between client and server configuration using the isWorker property.

The second argument to the webpack function is an object with the following properties:

  • dev: Boolean - Indicates if the compilation will be done in development
  • isWorker: Boolean - It's true for worker-side compilation, and false for client-side compilation
  • defaultLoaders: Object - Default loaders used internally by Flareact:
    • babel: Object - Default babel-loader configuration

Example usage of defaultLoaders.babel:

module.exports = {
  webpack: (config, options) => {
      test: /\.mdx/,
      use: [
          loader: "@mdx-js/loader",
          options: {},

    return config;