advanced-react-scripts/config/webpack.config.prod.js

// @remove-on-eject-begin
/**
 * Copyright (c) 2015-present, Facebook, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */
// @remove-on-eject-end
'use strict';

const path = require('path');
const webpack = require('webpack');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const ScriptExtHtmlWebpackPlugin = require('script-ext-html-webpack-plugin');
const UglifyJsPlugin = require('uglifyjs-webpack-plugin');
const ExtractTextPlugin = require('extract-text-webpack-plugin');
const ManifestPlugin = require('webpack-manifest-plugin');
const InterpolateHtmlPlugin = require('react-dev-utils-fresh/InterpolateHtmlPlugin');
const SWPrecacheWebpackPlugin = require('sw-precache-webpack-plugin');
const eslintFormatter = require('react-dev-utils-fresh/eslintFormatter');
const ModuleScopePlugin = require('react-dev-utils-fresh/ModuleScopePlugin');
const SpriteLoaderPlugin = require('svg-sprite-loader/plugin');
const paths = require('./paths');
const getClientEnvironment = require('./env');

// #advanced-react-scripts
const getAdvancedConfiguration = require('./advanced-react-scripts/config');

// Webpack uses `publicPath` to determine where the app is being served from.
// It requires a trailing slash, or the file assets will get an incorrect path.
const publicPath = paths.servedPath;
// Source maps are resource heavy and can cause out of memory issue for large source files.
const shouldUseSourceMap = process.env.GENERATE_SOURCEMAP !== 'false';
// `publicUrl` is just like `publicPath`, but we will provide it to our app
// as %PUBLIC_URL% in `index.html` and `process.env.PUBLIC_URL` in JavaScript.
// Omit trailing slash as %PUBLIC_URL%/xyz looks better than %PUBLIC_URL%xyz.
const publicUrl = publicPath.slice(0, -1);
// Get environment variables to inject into our app.
const env = getClientEnvironment(publicUrl);

// #advanced-react-scripts
const advancedConfiguration = getAdvancedConfiguration(env, false);

// Assert this just to be safe.
// Development builds of React are slow and not intended for production.
if (env.stringified['process.env'].NODE_ENV !== '"production"') {
  throw new Error('Production builds must have NODE_ENV=production.');
}

// Note: defined here because it will be used more than once.
const cssFilename = 'static/css/[name].[contenthash:8].css';

// This is the production configuration.
// It compiles slowly and is focused on producing a fast and minimal bundle.
// The development configuration is different and lives in a separate file.
module.exports = {
  // Don't attempt to continue if there are any errors.
  bail: true,
  // We generate sourcemaps in production. This is slow but gives good results.
  // You can exclude the *.map files from the build during deployment.
  devtool: shouldUseSourceMap ? 'source-map' : false,
  // In production, we only want to load the polyfills and the app code.
  entry: [require.resolve('./polyfills'), paths.appIndexJs],
  output: {
    // The build folder.
    path: paths.appBuild,
    // Generated JS file names (with nested folders).
    // There will be one main bundle, and one file per asynchronous chunk.
    // We don't currently advertise code splitting but Webpack supports it.
    filename: 'static/js/[name].[chunkhash:8].js',
    chunkFilename: 'static/js/[name].[chunkhash:8].chunk.js',
    // We inferred the "public path" (such as / or /my-project) from homepage.
    publicPath: publicPath,
    // Point sourcemap entries to original disk location (format as URL on Windows)
    devtoolModuleFilenameTemplate: info =>
      path
        .relative(paths.appSrc, info.absoluteResourcePath)
        .replace(/\\/g, '/'),
  },
  resolve: {
    // This allows you to set a fallback for where Webpack should look for modules.
    // We placed these paths second because we want `node_modules` to "win"
    // if there are any conflicts. This matches Node resolution mechanism.
    // https://github.com/facebook/create-react-app/issues/253
    modules: ['node_modules'].concat(
      // It is guaranteed to exist because we tweak it in `env.js`
      process.env.NODE_PATH.split(path.delimiter).filter(Boolean)
    ),
    // These are the reasonable defaults supported by the Node ecosystem.
    // We also include JSX as a common component filename extension to support
    // some tools, although we do not recommend using it, see:
    // https://github.com/facebook/create-react-app/issues/290
    // `web` extension prefixes have been added for better support
    // for React Native Web.
    extensions: ['.web.js', '.mjs', '.js', '.json', '.web.jsx', '.jsx'],
    alias: {
      // @remove-on-eject-begin
      // Resolve Babel runtime relative to react-scripts.
      // It usually still works on npm 3 without this but it would be
      // unfortunate to rely on, as react-scripts could be symlinked,
      // and thus @babel/runtime might not be resolvable from the source.
      '@babel/runtime': path.dirname(
        require.resolve('@babel/runtime/package.json')
      ),
      // @remove-on-eject-end
      // Support React Native Web
      // https://www.smashingmagazine.com/2016/08/a-glimpse-into-the-future-with-react-native-for-web/
      'react-native': 'react-native-web',
    },
    plugins: [
      // Prevents users from importing files from outside of src/ (or node_modules/).
      // This often causes confusion because we only process files within src/ with babel.
      // To fix this, we prevent you from importing files out of src/ -- if you'd like to,
      // please link the files into your node_modules/ and let module-resolution kick in.
      // Make sure your source files are compiled, as they will not be processed in any way.
      new ModuleScopePlugin(paths.appSrc, [paths.appPackageJson]),
    ],
  },
  module: {
    strictExportPresence: true,
    rules: [
      // Disable require.ensure as it's not a standard language feature.
      { parser: { requireEnsure: false } },

      // First, run the linter.
      // It's important to do this before Babel processes the JS.
      {
        test: /\.(js|jsx|mjs)$/,
        enforce: 'pre',
        use: [
          {
            options: {
              formatter: eslintFormatter,
              eslintPath: require.resolve('eslint'),
              // TODO: consider separate config for production,
              // e.g. to enable no-console and no-debugger only in production.
              baseConfig: {
                extends: [require.resolve('eslint-config-react-app-fresh')],
              },
              // @remove-on-eject-begin
              ignore: false,
              useEslintrc: false,
              // @remove-on-eject-end
            },
            loader: require.resolve('eslint-loader'),
          },
        ],
        include: paths.srcPaths,
        exclude: [/[/\\\\]node_modules[/\\\\]/],
      },
      {
        // "oneOf" will traverse all following loaders until one will
        // match the requirements. When no loader matches it will fall
        // back to the "file" loader at the end of the loader list.
        oneOf: [
          // "url" loader works just like "file" loader but it also embeds
          // assets smaller than specified size as data URLs to avoid requests.
          {
            test: [/\.bmp$/, /\.gif$/, /\.jpe?g$/, /\.png$/],
            loader: require.resolve('url-loader'),
            options: {
              limit: 10000,
              name: 'static/media/[name].[hash:8].[ext]',
            },
          },
          // Process application JS with Babel.
          // The preset includes JSX, Flow, and some ESnext features.
          {
            test: /\.(js|jsx|mjs)$/,
            include: paths.srcPaths,
            exclude: [/[/\\\\]node_modules[/\\\\]/],
            use: [
              // This loader parallelizes code compilation, it is optional but
              // improves compile time on larger projects
              require.resolve('thread-loader'),
              {
                loader: require.resolve('babel-loader'),
                options: {
                  // @remove-on-eject-begin
                  babelrc: false,
                  // @remove-on-eject-end
                  presets: [
                    require.resolve('babel-preset-react-app-fresh'),
                  ].concat(advancedConfiguration.babelPresets),
                  plugins: advancedConfiguration.babelPlugins,
                  compact: true,
                  highlightCode: true,
                },
              },
            ],
          },
          // Process any JS outside of the app with Babel.
          // Unlike the application JS, we only compile the standard ES features.
          {
            test: /\.js$/,
            use: [
              // This loader parallelizes code compilation, it is optional but
              // improves compile time on larger projects
              require.resolve('thread-loader'),
              {
                loader: require.resolve('babel-loader'),
                options: {
                  babelrc: false,
                  compact: false,
                  presets: [
                    require.resolve(
                      'babel-preset-react-app-fresh/dependencies'
                    ),
                  ],
                  cacheDirectory: true,
                  highlightCode: true,
                },
              },
            ],
          },
          ...advancedConfiguration.webpackLoaders,
          // "file" loader makes sure assets end up in the `build` folder.
          // When you `import` an asset, you get its filename.
          // This loader doesn't use a "test" so it will catch all modules
          // that fall through the other loaders.
          {
            loader: require.resolve('file-loader'),
            // Exclude `js` files to keep "css" loader working as it injects
            // it's runtime that would otherwise be processed through "file" loader.
            // Also exclude `html` and `json` extensions so they get processed
            // by webpacks internal loaders.
            exclude: [/\.(js|jsx|mjs)$/, /\.html$/, /\.json$/],
            options: {
              name: 'static/media/[name].[hash:8].[ext]',
            },
          },
          // ** STOP ** Are you adding a new loader?
          // Make sure to add the new loader(s) before the "file" loader.
        ],
      },
    ],
  },
  plugins: [
    // Makes some environment variables available in index.html.
    // The public URL is available as %PUBLIC_URL% in index.html, e.g.:
    // <link rel="shortcut icon" href="%PUBLIC_URL%/favicon.ico">
    // In production, it will be an empty string unless you specify "homepage"
    // in `package.json`, in which case it will be the pathname of that URL.
    new InterpolateHtmlPlugin(env.raw),
    // Generates an `index.html` file with the <script> injected.
    new HtmlWebpackPlugin({
      inject: true,
      template: paths.appHtml,
      minify: {
        removeComments: true,
        collapseWhitespace: true,
        removeRedundantAttributes: true,
        useShortDoctype: true,
        removeEmptyAttributes: true,
        removeStyleLinkTypeAttributes: true,
        keepClosingSlash: true,
        minifyJS: true,
        minifyCSS: true,
        minifyURLs: true,
      },
    }),
    ...(process.env.hasOwnProperty('REACT_APP_BUNDLE_ATTRIBUTE')
      ? [
          new ScriptExtHtmlWebpackPlugin({
            [process.env.REACT_APP_BUNDLE_ATTRIBUTE]: 'main',
          }),
        ]
      : []),
    ...(process.env.hasOwnProperty('REACT_APP_SVG_SPRITE_LOADER') &&
    process.env.REACT_APP_SVG_SPRITE_LOADER === 'true'
      ? [new SpriteLoaderPlugin()]
      : []),
    // Makes some environment variables available to the JS code, for example:
    // if (process.env.NODE_ENV === 'production') { ... }. See `./env.js`.
    // It is absolutely essential that NODE_ENV was set to production here.
    // Otherwise React will be compiled in the very slow development mode.
    new webpack.DefinePlugin(env.stringified),
    // Minify the code.
    new UglifyJsPlugin({
      uglifyOptions: {
        ecma: 8,
        compress: {
          warnings: false,
          // Disabled because of an issue with Uglify breaking seemingly valid code:
          // https://github.com/facebook/create-react-app/issues/2376
          // Pending further investigation:
          // https://github.com/mishoo/UglifyJS2/issues/2011
          comparisons: false,
        },
        mangle: {
          safari10: true,
        },
        output: {
          comments: false,
          // Turned on because emoji and regex is not minified properly using default
          // https://github.com/facebook/create-react-app/issues/2488
          ascii_only: true,
        },
      },
      // Use multi-process parallel running to improve the build speed
      // Default number of concurrent runs: os.cpus().length - 1
      parallel: true,
      // Enable file caching
      cache: true,
      sourceMap: shouldUseSourceMap,
    }),
    // Note: this won't work without ExtractTextPlugin.extract(..) in `loaders`.
    new ExtractTextPlugin({
      filename: cssFilename,
    }),
    // Generate a manifest file which contains a mapping of all asset filenames
    // to their corresponding output file so that tools can pick it up without
    // having to parse `index.html`.
    new ManifestPlugin({
      fileName: 'asset-manifest.json',
      publicPath: publicPath,
    }),
    // Generate a service worker script that will precache, and keep up to date,
    // the HTML & assets that are part of the Webpack build.
    new SWPrecacheWebpackPlugin({
      // By default, a cache-busting query parameter is appended to requests
      // used to populate the caches, to ensure the responses are fresh.
      // If a URL is already hashed by Webpack, then there is no concern
      // about it being stale, and the cache-busting can be skipped.
      dontCacheBustUrlsMatching: /\.\w{8}\./,
      filename: 'service-worker.js',
      logger(message) {
        if (message.indexOf('Total precache size is') === 0) {
          // This message occurs for every build and is a bit too noisy.
          return;
        }
        if (message.indexOf('Skipping static resource') === 0) {
          // This message obscures real errors so we ignore it.
          // https://github.com/facebook/create-react-app/issues/2612
          return;
        }
        console.log(message);
      },
      minify: true,
      // Don't precache sourcemaps (they're large) and build asset manifest:
      staticFileGlobsIgnorePatterns: [/\.map$/, /asset-manifest\.json$/],
      // `navigateFallback` and `navigateFallbackWhitelist` are disabled by default; see
      // https://github.com/facebook/create-react-app/blob/master/packages/react-scripts/template/README.md#service-worker-considerations
      // navigateFallback: publicUrl + '/index.html',
      // navigateFallbackWhitelist: [/^(?!\/__).*/],
    }),
    // Moment.js is an extremely popular library that bundles large locale files
    // by default due to how Webpack interprets its code. This is a practical
    // solution that requires the user to opt into importing specific locales.
    // https://github.com/jmblog/how-to-optimize-momentjs-with-webpack
    // You can remove this if you don't use Moment.js:
    new webpack.IgnorePlugin(/^\.\/locale$/, /moment$/),
  ],
  // Some libraries import Node modules but don't use them in the browser.
  // Tell Webpack to provide empty mocks for them so importing them works.
  node: {
    dgram: 'empty',
    fs: 'empty',
    net: 'empty',
    tls: 'empty',
    child_process: 'empty',
  },
};