nx/docs/shared/guides/customize-webpack.md

Customizing Webpack Config

For most apps, the default configuration of webpack is sufficient, but sometimes you need to tweak a setting in your webpack config. This guide explains how to make a small change without taking on the maintenance burden of the entire webpack config.

{% callout type="note" title="Angular" %} For Angular developers, use an executor like ngx-build-plus. {% /callout %}

In your project.json configuration for the @nrwl/web:webpack or @nrwl/node:webpack executor, set the webpackConfig option to point to your custom webpack config file. i.e. apps/my-app/custom-webpack.config.js

The custom webpack file contains a function that takes as input the existing webpack config and then returns a modified config object. context includes all the options specified for the executor.

apps/my-app/custom-webpack.config.js:

// Helper for combining webpack config objects
const { merge } = require('webpack-merge');

module.exports = (config, context) => {
  return merge(config, {
    // overwrite values here
  });
};

Also supports async functions

// Utility function for sleeping
const sleep = (n) => new Promise((resolve) => setTimeout(resolve, n));

module.exports = async (config, context) => {
  await sleep(10);
  return merge(config, {
    // overwrite values here
  });
};

Add a Loader

To add the css-loader to your config, install it and add the rule.

npm install -save-dev css-loader

const { merge } = require('webpack-merge');

module.exports = (config, context) => {
  return merge(config, {
    module: {
      rules: [
        {
          test: /\.css$/i,
          use: ['style-loader', 'css-loader'],
        },
      ],
    },
  });
};

Module Federation

If you use the Module Federation support from @nrwl/angular or @nrwl/react then you can customize your webpack configuration as follows.

const { merge } = require('webpack-merge');
const withModuleFederation = require('@nrwl/react/module-federation');
// or `const withModuleFederation = require('@nrwl/angular/module-federation');`

module.exports = async (config, context) => {
  const federatedModules = await withModuleFederation({
    // your options here
  });

  return merge(federatedModules(config, context), {
    // overwrite values here
  });
};

Reference the webpack documentation for details on the structure of the webpack config object.

Next.js Applications

Next.js supports webpack customization in the next.config.js file.

const { withNx } = require('@nrwl/next/plugins/with-nx');

const nextConfig = {
  webpack: (
    config,
    { buildId, dev, isServer, defaultLoaders, nextRuntime, webpack }
  ) => {
    // Important: return the modified config
    return config;
  },
};

return withNx(nextConfig);

Read the official documentation for more details.