webpack.config.prod.js

'use strict';

const autoprefixer = require('autoprefixer');
const path = require('path');
const webpack = require('webpack');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const UglifyJsPlugin = require('uglifyjs-webpack-plugin');
const MiniCssExtractPlugin = require('mini-css-extract-plugin');
const ManifestPlugin = require('webpack-manifest-plugin');
const InterpolateHtmlPlugin = require('react-dev-utils/InterpolateHtmlPlugin');
const CopyPlugin = require('copy-webpack-plugin');
const workboxPlugin = require('workbox-webpack-plugin');
const paths = require('../config/paths');
const getClientEnvironment = require('./env');
const OptimizeCSSAssetsPlugin = require('optimize-css-assets-webpack-plugin');
const safePostCssParser = require('postcss-safe-parser');

// 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);

const useDebugger = process.env.ELM_DEBUGGER === 'true';

// 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 = {
  mode: 'production',
  // 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, '/'),
  },
  optimization: {
    minimizer: [
      new UglifyJsPlugin({
        uglifyOptions: {
          warnings: false,
          // ES5 is required in the minified code if you want compatibility with IE11,
          // otherwise you can bump it up to ES8
          ecma: 5,
          // Compression settings mostly based on <https://guide.elm-lang.org/optimization/asset_size.html>
          compress: {
            passes: 2,
            // 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,
            pure_getters: true,
            keep_fargs: false,
            unsafe_comps: true,
            unsafe: true,
            pure_funcs: [
              'A2',
              'A3',
              'A4',
              'A5',
              'A6',
              'A7',
              'A8',
              'A9',
              'F2',
              'F3',
              'F4',
              'F5',
              'F6',
              'F7',
              'F8',
              'F9',
            ],
          },
          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,
      }),
      new OptimizeCSSAssetsPlugin({
        cssProcesorOptions: {
          parser: safePostCssParser,
          map: shouldUseSourceMap
            ? {
                // This forces the sourcemap to be output into a separate file
                inline: false,
                // This appends the sourceMappingURL to the end of the css file,
                // helping the browser find the sourcemap
                annotation: true,
              }
            : false,
        },
      }),
    ],
    // Automatically split vendor and commons
    // https://twitter.com/wSokra/status/969633336732905474
    splitChunks: {
      chunks: 'all',
    },
    // Keep the runtime chunk seperated to enable long term caching
    // https://twitter.com/wSokra/status/969679223278505985
    runtimeChunk: true,
  },
  resolve: {
    modules: ['node_modules'],
    extensions: ['.js', '.mjs', '.elm'],
  },
  module: {
    strictExportPresence: true,

    rules: [
      {
        test: /\.js$/,
        exclude: [/[/\\\\]elm-stuff[/\\\\]/, /[/\\\\]node_modules[/\\\\]/],
        loader: require.resolve('babel-loader'),
        options: {
          // Latest stable ECMAScript features
          presets: [
            [
              require.resolve('@babel/preset-env'),
              {
                // `entry` transforms `@babel/polyfill` into individual requires for
                // the targeted browsers. This is safer than `usage` which performs
                // static code analysis to determine what's required.
                // This is probably a fine default to help trim down bundles when
                // end-users inevitably import '@babel/polyfill'.
                useBuiltIns: 'entry',
                // Set the corejs version we are using to avoid warnings in console
                corejs: 3,
                // Do not transform modules to CJS
                modules: false,
              },
            ],
          ],
          plugins: [
            // Polyfills the runtime needed for async/await and generators
            [
              require('@babel/plugin-transform-runtime').default,
              {
                helpers: false,
                regenerator: true,
              },
            ],
          ],
        },
      },
      // Process any JS outside of the app with Babel.
      // Unlike the application JS, we only compile the standard ES features.
      {
        test: /\.m?js$/,
        use: [
          {
            loader: require.resolve('babel-loader'),
            options: {
              babelrc: false,
              compact: false,
              presets: [
                [
                  // Latest stable ECMAScript features
                  require('@babel/preset-env').default,
                  {
                    // Do not transform modules to CJS
                    modules: false,
                  },
                ],
              ],
              cacheDirectory: true,
              highlightCode: true,
            },
          },
        ],
      },
      {
        test: /\.elm$/,
        exclude: [/[/\\\\]elm-stuff[/\\\\]/, /[/\\\\]node_modules[/\\\\]/],
        use: [
          // string-replace-loader works as InterpolateHtmlPlugin for Elm,
          // it replaces all of the %PUBLIC_URL% with the URL of your
          // application, so you could serve static assets outside of the
          // module system.
          {
            loader: require.resolve('string-replace-loader'),
            query: {
              search: '%PUBLIC_URL%',
              replace: publicUrl,
              flags: 'g',
            },
          },
          {
            loader: require.resolve('elm-asset-webpack-loader'),
          },
          {
            // Use the local installation of elm make
            loader: require.resolve('elm-webpack-loader'),
            options: {
              // If ELM_DEBUGGER was set to "true", enable it. Otherwise
              // for invalid values, "false" and as a default, disable it
              debug: useDebugger,
              optimize: !useDebugger,
              pathToElm: paths.elm,
            },
          },
        ],
      },

      // "postcss" loader applies autoprefixer to our CSS.
      // "css" loader resolves paths in CSS and adds assets as dependencies.
      // `MiniCSSExtractPlugin` extracts styles into CSS
      // files. If you use code splitting, async bundles will have their own separate CSS chunk file.
      // By default we support CSS Modules with the extension .module.css
      {
        test: /\.css$/,
        exclude: /\.module\.css$/,
        use: [
          MiniCssExtractPlugin.loader,
          {
            loader: require.resolve('css-loader'),
            options: {
              importLoaders: 1,
              sourceMap: shouldUseSourceMap,
            },
          },
          {
            loader: require.resolve('postcss-loader'),
            options: {
              // Necessary for external CSS imports to work
              // https://github.com/facebook/create-react-app/issues/2677
              postcssOptions: {
                plugins: () => [
                  require('postcss-flexbugs-fixes'),
                  autoprefixer({
                    flexbox: 'no-2009',
                  }),
                ],
              },
            },
          },
        ],
      },

      {
        exclude: [
          /\.html$/,
          /\.js$/,
          /\.mjs$/,
          /\.elm$/,
          /\.css$/,
          /\.scss$/,
          /\.sass$/,
          /\.json$/,
          /\.svg$/,
        ],
        loader: require.resolve('url-loader'),
        options: {
          limit: 10000,
          name: 'static/media/[name].[hash:8].[ext]',
        },
      },
      // "file" loader for svg
      {
        test: /\.svg$/,
        loader: require.resolve('file-loader'),
        options: {
          name: 'static/media/[name].[hash:8].[ext]',
        },
      },
    ],
  },
  plugins: [
    // 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,
      },
    }),
    // Makes some environment variables available in index.html.
    // The public URL is available as %PUBLIC_URL% in index.html, e.g.:
    // <link rel="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(HtmlWebpackPlugin, env.raw),
    // 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),
    // Note: this won't work without ExtractTextPlugin.extract(..) in `loaders`.
    new MiniCssExtractPlugin({
      // Options similar to the same options in webpackOptions.output
      // both options are optional
      filename: 'static/css/[name].[contenthash:8].css',
      chunkFilename: 'static/css/[name].[contenthash:8].chunk.css',
    }),
    // 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,
    }),
    // Copies the public folder to the build folder
    new CopyPlugin({
      patterns: [{ from: './public/', to: './' }],
    }),
    // Generate a service worker script that will precache, and keep up to date,
    // the HTML & assets that are part of the Webpack build.
    new workboxPlugin.GenerateSW({
      swDest: './service-worker.js',
      skipWaiting: true,
      clientsClaim: true,
    }),
  ],
  // 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',
  },

  // Turn off performance processing because we utilize
  // our own hints via the FileSizeReporter
  performance: false,
};