create-react-app v1.3.1 unified webpack config

get-config.js

const getClientEnvironment = require('../env');
const paths = require('../paths');

module.exports = (isProd) => {
    // 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.
    // In development, we always serve from the root. This makes config easier.
    const publicPath = isProd ? paths.servedPath : '/';

    // `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_PATH%/xyz looks better than %PUBLIC_PATH%xyz.
    const publicUrl = isProd ? publicPath.slice(0, -1) : '';

    // Get environment variables to inject into our app.
    const env = getClientEnvironment(publicUrl);

    // Assert this just to be safe.
    // Development builds of React are slow and not intended for production.
    if (isProd && 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 = isProd ? 'static/css/[name].[contenthash:8].css' : null;

    return {
        paths,
        publicPath,
        publicUrl,
        env,
        cssFilename,
    }
}

index.js

'use strict';

const path = require('path');

const ModuleScopePlugin = require('react-dev-utils/ModuleScopePlugin');

const getConfig = require('./get-config');
const { keepIf, nonEmpty } = require('./util');
const getModuleConfig = require('./module');
const getPlugins = require('./plugins');

module.exports = (isProd) => {
    const isDev = !isProd;

    const {
        paths,
        publicPath,
        publicUrl,
        env,
        cssFilename,
        extractTextPluginOptions
    } = getConfig(isProd);

    return {
        // Don't attempt to continue if there are any errors.
        bail: isProd,

        // We generate sourcemaps in production. This is slow but gives good results.
        // You can exclude the *.map files from the build during deployment.

        // In development you may want 'eval' instead if you prefer to see the compiled output in DevTools.
        // See the discussion in https://github.com/facebookincubator/create-react-app/issues/343.
        devtool: isProd ? 'source-map' : 'cheap-module-source-map',

        // These are the "entry points" to our application.
        // This means they will be the "root" imports that are included in JS bundle.
        // The first two entry points enable "hot" CSS and auto-refreshes for JS.
        entry: nonEmpty([
            // Include an alternative client for WebpackDevServer. A client's job is to
            // connect to WebpackDevServer by a socket and get notified about changes.
            // When you save a file, the client will either apply hot updates (in case
            // of CSS changes), or refresh the page (in case of JS changes). When you
            // make a syntax error, this client will display a syntax error overlay.
            // Note: instead of the default WebpackDevServer client, we use a custom one
            // to bring better experience for Create React App users. You can replace
            // the line below with these two lines if you prefer the stock client:
            // require.resolve('webpack-dev-server/client') + '?/',
            // require.resolve('webpack/hot/dev-server'),
            keepIf(isDev, require.resolve('react-dev-utils/webpackHotDevClient')),
            // We ship a few polyfills by default:
            require.resolve('../polyfills'),
            // Errors should be considered fatal in development
            keepIf(isDev, require.resolve('react-error-overlay')),
            // Finally, this is your app's code:
            paths.appIndexJs,
            // We include the app code last so that if there is a runtime error during
            // initialization, it doesn't blow up the WebpackDevServer client, and
            // changing JS code would still trigger a refresh.
        ]),

        output: {
            // The build folder.
            path: paths.appBuild,
            // Add /* filename */ comments to generated require()s in the output.
            pathinfo: isDev,
            // DEV: This does not produce a real file. It's just the virtual path that is
            // served by WebpackDevServer in development. This is the JS bundle
            // containing code from all our entry points, and the Webpack runtime.
            // PROD: 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: isProd ? 'static/js/[name].[chunkhash:8].js' : 'static/js/bundle.js',
            // There are also additional JS chunk files if you use code splitting.
            chunkFilename: isProd ? 'static/js/[name].[chunkhash:8].chunk.js' : 'static/js/[name].chunk.js',
            // This is the URL that app is served from. We use "/" in development.
            publicPath: publicPath,
            // Point sourcemap entries to original disk location
            devtoolModuleFilenameTemplate: info =>
                isProd
                    ? path.relative(paths.appSrc, info.absoluteResourcePath)
                    : path.resolve(info.absoluteResourcePath),
        },

        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/facebookincubator/create-react-app/issues/253
            modules: ['node_modules', paths.appNodeModules].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/facebookincubator/create-react-app/issues/290
            extensions: ['.js', '.json', '.jsx'],
            alias: {
                // 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),
            ],
        },

        module: getModuleConfig(isProd, { paths, cssFilename, publicPath }),

        plugins: getPlugins(isProd, { paths, env, cssFilename, publicUrl }),

        // 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: {
            fs: 'empty',
            net: 'empty',
            tls: 'empty',
        },
        // Turn off performance hints during development because we don't do any
        // splitting or minification in interest of speed. These warnings become
        // cumbersome.
        performance: keepIf(isDev, {
            hints: false,
        }),
    }
}

module.js

const autoprefixer = require('autoprefixer');
const eslintFormatter = require('react-dev-utils/eslintFormatter');

const ExtractTextPlugin = require('extract-text-webpack-plugin');

const { keepIf } = require('./util');

const BROWSERS_SUPPORT = [
    '>1%',
    'last 4 versions',
    'Firefox ESR',
    'not ie < 9', // React doesn't support IE8 anyway
];

const POSTCSS_OPTIONS = {
    ident: 'postcss', // https://webpack.js.org/guides/migrating/#complex-options
    plugins: () => [
        require('postcss-flexbugs-fixes'),
        autoprefixer({
            browsers: BROWSERS_SUPPORT,
            flexbox: 'no-2009',
        }),
    ],
};

const postcssLoader = {
    loader: require.resolve('postcss-loader'),
    options: POSTCSS_OPTIONS,
};

const styleLoader = require.resolve('style-loader');

const cssLoader = require.resolve('css-loader');

module.exports = (isProd, { paths, cssFilename, publicPath }) => {
    // Some apps do not use client-side routing with pushState.
    // For these, "homepage" can be set to "." to enable relative asset paths.
    const shouldUseRelativeAssetPaths = publicPath === './';

    // ExtractTextPlugin expects the build output to be flat.
    // (See https://github.com/webpack-contrib/extract-text-webpack-plugin/issues/27)
    // However, our output is structured with css, js and media folders.
    // To have this structure working with relative paths, we have to use custom options.
    const extractTextPluginOptions = isProd && shouldUseRelativeAssetPaths
    ? // Making sure that the publicPath goes back to to build folder.
        { publicPath: Array(cssFilename.split('/').length).join('../') }
    : {};

    return {
        strictExportPresence: true,
        rules: [
            // TODO: Disable require.ensure as it's not a standard language feature.
            // We are waiting for https://github.com/facebookincubator/create-react-app/issues/2176.
            // { parser: { requireEnsure: false } },

            // First, run the linter.
            // It's important to do this before Babel processes the JS.
            {
                test: /\.(js|jsx)$/,
                enforce: 'pre',
                use: [
                    {
                        options: {
                            formatter: eslintFormatter,
                        },
                        loader: require.resolve('eslint-loader'),
                    }, 
                ],
                include: paths.appSrc,
            },
            // ** ADDING/UPDATING LOADERS **
            // The "file" loader handles all assets unless explicitly excluded.
            // The `exclude` list *must* be updated with every change to loader extensions.
            // When adding a new loader, you must add its `test`
            // as a new entry in the `exclude` list for "file" loader.

            // "file" loader makes sure those assets get served by WebpackDevServer.
            // When you `import` an asset, you get its (virtual) filename.
            // In production, they would get copied to the `build` folder.
            {
                exclude: [
                    /\.html$/,
                    /\.(js|jsx)$/,
                    /\.css$/,
                    /\.json$/,
                    /\.bmp$/,
                    /\.gif$/,
                    /\.jpe?g$/,
                    /\.png$/,
                ],
                loader: require.resolve('file-loader'),
                options: {
                    name: 'static/media/[name].[hash:8].[ext]',
                },
            },
            // "url" loader works like "file" loader except that it embeds assets
            // smaller than specified limit in bytes as data URLs to avoid requests.
            // A missing `test` is equivalent to a match.
            {
                test: [/\.bmp$/, /\.gif$/, /\.jpe?g$/, /\.png$/],
                loader: require.resolve('url-loader'),
                options: {
                    limit: 10000,
                    name: 'static/media/[name].[hash:8].[ext]',
                },
            },
            // Process JS with Babel.
            {
                test: /\.(js|jsx)$/,
                include: paths.appSrc,
                loader: require.resolve('babel-loader'),
                options: isProd ? {
                    // This is a feature of `babel-loader` for webpack (not Babel itself).
                    // It enables caching results in ./node_modules/.cache/babel-loader/
                    // directory for faster rebuilds.
                    cacheDirectory: true,
                } : undefined,
            },
            // "postcss" loader applies autoprefixer to our CSS.
            // "css" loader resolves paths in CSS and adds assets as dependencies.
            // "style" loader turns CSS into JS modules that inject <style> tags.
            // In production, we use a plugin to extract that CSS to a file, but
            // in development "style" loader enables hot editing of CSS.
            {
                test: /\.css$/,
                use: keepIf(!isProd, [
                    styleLoader,
                    {
                        loader: cssLoader,
                        options: {
                            importLoaders: 1,
                        },
                    },
                    postcssLoader,
                ]),
                loader: keepIf(isProd, ExtractTextPlugin.extract(Object.assign(
                    {
                        fallback: styleLoader,
                        use: [
                            {
                                loader: cssLoader,
                                options: {
                                importLoaders: 1,
                                minimize: true,
                                sourceMap: true,
                                },
                            },
                            postcssLoader,
                        ],
                    },
                    extractTextPluginOptions
                ))),
                // Note: this won't work without `new ExtractTextPlugin()` in `plugins`.
            },
            // ** STOP ** Are you adding a new loader?
            // Remember to add the new extension(s) to the "file" loader exclusion list.
        ],
    }
}

plugins.js

const webpack = require('webpack');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const ExtractTextPlugin = require('extract-text-webpack-plugin');
const CaseSensitivePathsPlugin = require('case-sensitive-paths-webpack-plugin');
const InterpolateHtmlPlugin = require('react-dev-utils/InterpolateHtmlPlugin');
const WatchMissingNodeModulesPlugin = require('react-dev-utils/WatchMissingNodeModulesPlugin');
const ManifestPlugin = require('webpack-manifest-plugin');
const SWPrecacheWebpackPlugin = require('sw-precache-webpack-plugin');

const { keepIf, nonEmpty } = require('./util');

module.exports = (isProd, { paths, env, cssFilename, publicUrl }) => {
    const isDev = !isProd;

    const devPlugins = !isDev ? [] : [
        // This is necessary to emit hot updates (currently CSS only):
        new webpack.HotModuleReplacementPlugin(),
        // Watcher doesn't work well if you mistype casing in a path so we use
        // a plugin that prints an error when you attempt to do this.
        // See https://github.com/facebookincubator/create-react-app/issues/240
        new CaseSensitivePathsPlugin(),
        // If you require a missing module and then `npm install` it, you still have
        // to restart the development server for Webpack to discover it. This plugin
        // makes the discovery automatic so you don't have to restart.
        // See https://github.com/facebookincubator/create-react-app/issues/186
        new WatchMissingNodeModulesPlugin(paths.appNodeModules),
    ]

    const prodPlugins = !isProd ? [] : [
        // Minify the code.
        new webpack.optimize.UglifyJsPlugin({
            compress: {
                warnings: false,
                // Disabled because of an issue with Uglify breaking seemingly valid code:
                // https://github.com/facebookincubator/create-react-app/issues/2376
                // Pending further investigation:
                // https://github.com/mishoo/UglifyJS2/issues/2011
                comparisons: false,
            },
            output: {
                comments: false,
            },
            sourceMap: true,
        }),
        // 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',
        }),
        // 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;
                }
                console.log(message);
            },
            minify: true,
            // For unknown URLs, fallback to the index page
            navigateFallback: publicUrl + '/index.html',
            // Ignores URLs starting from /__ (useful for Firebase):
            // https://github.com/facebookincubator/create-react-app/issues/2237#issuecomment-302693219
            navigateFallbackWhitelist: [/^(?!\/__).*/],
            // Don't precache sourcemaps (they're large) and build asset manifest:
            staticFileGlobsIgnorePatterns: [/\.map$/, /asset-manifest\.json$/],
            // Work around Windows path issue in SWPrecacheWebpackPlugin:
            // https://github.com/facebookincubator/create-react-app/issues/2235
            stripPrefix: paths.appBuild.replace(/\\/g, '/') + '/',
        }),
    ]

    return nonEmpty([
        // 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 development, this will be an empty string.
        // 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: keepIf(isProd, {
                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 to the JS code, for example:
        // if (process.env.NODE_ENV === 'development') { ... }. See `./env.js`.
        new webpack.DefinePlugin(env.stringified),

        ...devPlugins,
        ...prodPlugins,

        // 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$/, /moment$/),
    ])
}

util.js

exports.keepIf = (cond, val) => cond ? val : undefined;

exports.nonEmpty = arr => arr.filter(Boolean);