Updated coding styles and test configs

config/env.js

@@ -1,4 +1,3 @@
-'use strict';
 
 const fs = require('fs');
 const path = require('path');
@@ -7,7 +6,8 @@ const paths = require('./paths');
 // Make sure that including paths.js after env.js will read .env variables.
 delete require.cache[require.resolve('./paths')];
 
-const NODE_ENV = process.env.NODE_ENV;
+const { NODE_ENV } = process.env;
+
 if (!NODE_ENV) {
   throw new Error(
     'The NODE_ENV environment variable is required but was not specified.'
@@ -18,6 +18,7 @@ if (!NODE_ENV) {
 const dotenvFiles = [
   `${paths.dotenv}.${NODE_ENV}.local`,
   `${paths.dotenv}.${NODE_ENV}`,
+
   // Don't include `.env.local` for `test` environment
   // since normally you expect tests to produce the same
   // results for everyone
@@ -30,7 +31,7 @@ const dotenvFiles = [
 // that have already been set.  Variable expansion is supported in .env files.
 // https://github.com/motdotla/dotenv
 // https://github.com/motdotla/dotenv-expand
-dotenvFiles.forEach(dotenvFile => {
+dotenvFiles.forEach((dotenvFile) => {
   if (fs.existsSync(dotenvFile)) {
     require('dotenv-expand')(
       require('dotenv').config({
@@ -50,10 +51,11 @@ dotenvFiles.forEach(dotenvFile => {
 // https://github.com/facebook/create-react-app/issues/1023#issuecomment-265344421
 // We also resolve them to make sure all tools using them work consistently.
 const appDirectory = fs.realpathSync(process.cwd());
+
 process.env.NODE_PATH = (process.env.NODE_PATH || '')
   .split(path.delimiter)
-  .filter(folder => folder && !path.isAbsolute(folder))
+  .filter((folder) => folder && !path.isAbsolute(folder))
-  .map(folder => path.resolve(appDirectory, folder))
+  .map((folder) => path.resolve(appDirectory, folder))
   .join(path.delimiter);
 
 // Grab NODE_ENV and REACT_APP_* environment variables and prepare them to be
@@ -62,16 +64,19 @@ const REACT_APP = /^REACT_APP_/i;
 
 function getClientEnvironment(publicUrl) {
   const raw = Object.keys(process.env)
-    .filter(key => REACT_APP.test(key))
+    .filter((key) => REACT_APP.test(key))
     .reduce(
       (env, key) => {
         env[key] = process.env[key];
+
         return env;
       },
       {
+
         // Useful for determining whether we’re running in production mode.
         // Most importantly, it switches React into the correct mode.
         NODE_ENV: process.env.NODE_ENV || 'development',
+
         // Useful for resolving the correct path to static assets in `public`.
         // For example, <img src={process.env.PUBLIC_URL + '/img/logo.png'} />.
         // This should only be used as an escape hatch. Normally you would put
@@ -79,10 +84,12 @@ function getClientEnvironment(publicUrl) {
         PUBLIC_URL: publicUrl,
       }
     );
+
   // Stringify all values so we can feed into Webpack DefinePlugin
   const stringified = {
     'process.env': Object.keys(raw).reduce((env, key) => {
       env[key] = JSON.stringify(raw[key]);
+
       return env;
     }, {}),
   };

config/jest/cssTransform.js

@@ -1,4 +1,3 @@
-'use strict';
 
 // This is a custom Jest transformer turning style imports into empty objects.
 // http://facebook.github.io/jest/docs/en/webpack.html

config/jest/fileTransform.js

@@ -1,4 +1,3 @@
-'use strict';
 
 const path = require('path');
 

config/paths.js

@@ -1,4 +1,3 @@
-'use strict';
 
 const path = require('path');
 const fs = require('fs');
@@ -7,22 +6,23 @@ const url = require('url');
 // Make sure any symlinks in the project folder are resolved:
 // https://github.com/facebook/create-react-app/issues/637
 const appDirectory = fs.realpathSync(process.cwd());
-const resolveApp = relativePath => path.resolve(appDirectory, relativePath);
+const resolveApp = (relativePath) => path.resolve(appDirectory, relativePath);
 
 const envPublicUrl = process.env.PUBLIC_URL;
 
 function ensureSlash(inputPath, needsSlash) {
   const hasSlash = inputPath.endsWith('/');
+
   if (hasSlash && !needsSlash) {
     return inputPath.substr(0, inputPath.length - 1);
   } else if (!hasSlash && needsSlash) {
     return `${inputPath}/`;
-  } else {
-    return inputPath;
-  }
   }
 
-const getPublicUrl = appPackageJson =>
+  return inputPath;
+}
+
+const getPublicUrl = (appPackageJson) =>
   envPublicUrl || require(appPackageJson).homepage;
 
 // We use `PUBLIC_URL` environment variable or "homepage" field to infer
@@ -35,6 +35,7 @@ function getServedPath(appPackageJson) {
   const publicUrl = getPublicUrl(appPackageJson);
   const servedUrl =
     envPublicUrl || (publicUrl ? url.parse(publicUrl).pathname : '/');
+
   return ensureSlash(servedUrl, true);
 }
 
@@ -54,9 +55,8 @@ const moduleFileExtensions = [
 
 // Resolve file paths in the same order as webpack
 const resolveModule = (resolveFn, filePath) => {
-  const extension = moduleFileExtensions.find(extension =>
+  const extension = moduleFileExtensions.find((extension) =>
-    fs.existsSync(resolveFn(`${filePath}.${extension}`))
+    fs.existsSync(resolveFn(`${filePath}.${extension}`)));
-  );
 
   if (extension) {
     return resolveFn(`${filePath}.${extension}`);

config/webpack.config.js

@@ -1,4 +1,3 @@
-'use strict';
 
 const fs = require('fs');
 const path = require('path');
@@ -18,15 +17,15 @@ const WorkboxWebpackPlugin = require('workbox-webpack-plugin');
 const WatchMissingNodeModulesPlugin = require('react-dev-utils/WatchMissingNodeModulesPlugin');
 const ModuleScopePlugin = require('react-dev-utils/ModuleScopePlugin');
 const getCSSModuleLocalIdent = require('react-dev-utils/getCSSModuleLocalIdent');
-const paths = require('./paths');
-const getClientEnvironment = require('./env');
 const ModuleNotFoundPlugin = require('react-dev-utils/ModuleNotFoundPlugin');
 const ForkTsCheckerWebpackPlugin = require('fork-ts-checker-webpack-plugin-alt');
 const typescriptFormatter = require('react-dev-utils/typescriptFormatter');
-
+const getClientEnvironment = require('./env');
+const paths = require('./paths');
 
 // Source maps are resource heavy and can cause out of memory issue for large source files.
 const shouldUseSourceMap = process.env.GENERATE_SOURCEMAP !== 'false';
+
 // Some apps do not need the benefits of saving a web request, so not inlining the chunk
 // makes for a smoother build process.
 const shouldInlineRuntimeChunk = process.env.INLINE_RUNTIME_CHUNK !== 'false';
@@ -42,7 +41,8 @@ const sassModuleRegex = /\.module\.(scss|sass)$/;
 
 // This is the production and development configuration.
 // It is focused on developer experience, fast rebuilds, and a minimal bundle.
-module.exports = function(webpackEnv) {
+/* eslint-disable complexity */
+module.exports = (webpackEnv) => {
   const isEnvDevelopment = webpackEnv === 'development';
   const isEnvProduction = webpackEnv === 'production';
 
@@ -52,6 +52,7 @@ module.exports = function(webpackEnv) {
   const publicPath = isEnvProduction
     ? paths.servedPath
     : isEnvDevelopment && '/';
+
   // 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 === './';
@@ -62,6 +63,7 @@ module.exports = function(webpackEnv) {
   const publicUrl = isEnvProduction
     ? publicPath.slice(0, -1)
     : isEnvDevelopment && '';
+
   // Get environment variables to inject into our app.
   const env = getClientEnvironment(publicUrl);
 
@@ -81,11 +83,13 @@ module.exports = function(webpackEnv) {
         options: cssOptions,
       },
       {
+
         // Options for PostCSS as we reference these options twice
         // Adds vendor prefixing based on your specified browser support in
         // package.json
         loader: require.resolve('postcss-loader'),
         options: {
+
           // Necessary for external CSS imports to work
           // https://github.com/facebook/create-react-app/issues/2677
           ident: 'postcss',
@@ -102,6 +106,7 @@ module.exports = function(webpackEnv) {
         },
       },
     ].filter(Boolean);
+
     if (preProcessor) {
       loaders.push({
         loader: require.resolve(preProcessor),
@@ -110,11 +115,13 @@ module.exports = function(webpackEnv) {
         },
       });
     }
+
     return loaders;
   };
 
   return {
     mode: isEnvProduction ? 'production' : isEnvDevelopment && 'development',
+
     // Stop compilation early in production
     bail: isEnvProduction,
     devtool: isEnvProduction
@@ -122,9 +129,11 @@ module.exports = function(webpackEnv) {
         ? 'source-map'
         : false
       : isEnvDevelopment && '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.
     entry: [
+
       // 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
@@ -137,45 +146,55 @@ module.exports = function(webpackEnv) {
       // require.resolve('webpack/hot/dev-server'),
       isEnvDevelopment &&
         require.resolve('react-dev-utils/webpackHotDevClient'),
+
       // 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.
     ].filter(Boolean),
     output: {
+
       // The build folder.
       path: isEnvProduction ? paths.appBuild : undefined,
+
       // Add /* filename */ comments to generated require()s in the output.
       pathinfo: isEnvDevelopment,
+
       // There will be one main bundle, and one file per asynchronous chunk.
       // In development, it does not produce real files.
       filename: isEnvProduction
         ? 'static/js/[name].[chunkhash:8].js'
         : isEnvDevelopment && 'static/js/bundle.js',
+
       // There are also additional JS chunk files if you use code splitting.
       chunkFilename: isEnvProduction
         ? 'static/js/[name].[chunkhash:8].chunk.js'
         : isEnvDevelopment && 'static/js/[name].chunk.js',
+
       // We inferred the "public path" (such as / or /my-project) from homepage.
       // We use "/" in development.
-      publicPath: publicPath,
+      publicPath,
+
       // Point sourcemap entries to original disk location (format as URL on Windows)
       devtoolModuleFilenameTemplate: isEnvProduction
-        ? info =>
+        ? (info) =>
           path
             .relative(paths.appSrc, info.absoluteResourcePath)
             .replace(/\\/g, '/')
         : isEnvDevelopment &&
-          (info => path.resolve(info.absoluteResourcePath).replace(/\\/g, '/')),
+          ((info) => path.resolve(info.absoluteResourcePath).replace(/\\/g, '/')),
     },
     optimization: {
       minimize: isEnvProduction,
       minimizer: [
+
         // This is only used in production mode
         new TerserPlugin({
           terserOptions: {
             parse: {
+
               // we want terser to parse ecma 8 code. However, we don't want it
               // to apply any minfication steps that turns valid ecma 5 code
               // into invalid ecma 5 code. This is why the 'compress' and 'output'
@@ -186,11 +205,13 @@ module.exports = function(webpackEnv) {
             compress: {
               ecma: 5,
               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,
+
               // Disabled because of an issue with Terser breaking valid code:
               // https://github.com/facebook/create-react-app/issues/5250
               // Pending futher investigation:
@@ -203,27 +224,33 @@ module.exports = function(webpackEnv) {
             output: {
               ecma: 5,
               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,
         }),
+
         // This is only used in production mode
         new OptimizeCSSAssetsPlugin({
           cssProcessorOptions: {
             parser: safePostCssParser,
             map: shouldUseSourceMap
               ? {
+
                 // `inline: false` forces the sourcemap to be output into a
                 // separate file
                 inline: false,
+
                 // `annotation: true` appends the sourceMappingURL to the end of
                 // the css file, helping the browser find the sourcemap
                 annotation: true,
@@ -232,6 +259,7 @@ module.exports = function(webpackEnv) {
           },
         }),
       ],
+
       // Automatically split vendor and commons
       // https://twitter.com/wSokra/status/969633336732905474
       // https://medium.com/webpack/webpack-4-code-splitting-chunk-graph-and-the-splitchunks-optimization-be739a861366
@@ -239,19 +267,23 @@ module.exports = function(webpackEnv) {
         chunks: 'all',
         name: false,
       },
+
       // Keep the runtime chunk separated to enable long term caching
       // https://twitter.com/wSokra/status/969679223278505985
       runtimeChunk: true,
     },
     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:
@@ -259,17 +291,20 @@ module.exports = function(webpackEnv) {
       // `web` extension prefixes have been added for better support
       // for React Native Web.
       extensions: paths.moduleFileExtensions
-        .map(ext => `.${ext}`)
+        .map((ext) => `.${ext}`)
-        .filter(ext => useTypeScript || !ext.includes('ts')),
+        .filter((ext) => useTypeScript || !ext.includes('ts')),
       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: [
+
         // Adds support for installing with Plug'n'Play, leading to faster installs and adding
         // guards against forgotten dependencies and such.
         PnpWebpackPlugin,
+
         // 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,
@@ -280,6 +315,7 @@ module.exports = function(webpackEnv) {
     },
     resolveLoader: {
       plugins: [
+
         // Also related to Plug'n'Play, but this time it tells Webpack to load its loaders
         // from the current package.
         PnpWebpackPlugin.moduleLoader(module),
@@ -288,6 +324,7 @@ module.exports = function(webpackEnv) {
     module: {
       strictExportPresence: true,
       rules: [
+
         // Disable require.ensure as it's not a standard language feature.
         { parser: { requireEnsure: false } },
 
@@ -309,10 +346,12 @@ module.exports = function(webpackEnv) {
           include: paths.appSrc,
         },
         {
+
           // "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 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.
@@ -324,6 +363,7 @@ module.exports = function(webpackEnv) {
                 name: 'static/media/[name].[hash:8].[ext]',
               },
             },
+
             // Process application JS with Babel.
             // The preset includes JSX, Flow, TypeScript, and some ESnext features.
             {
@@ -348,6 +388,7 @@ module.exports = function(webpackEnv) {
                     },
                   ],
                 ],
+
                 // 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.
@@ -356,6 +397,7 @@ module.exports = function(webpackEnv) {
                 compact: isEnvProduction,
               },
             },
+
             // Process any JS outside of the app with Babel.
             // Unlike the application JS, we only compile the standard ES features.
             {
@@ -382,6 +424,7 @@ module.exports = function(webpackEnv) {
                 sourceMaps: false,
               },
             },
+
             // "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.
@@ -396,12 +439,14 @@ module.exports = function(webpackEnv) {
                 importLoaders: 1,
                 sourceMap: isEnvProduction && shouldUseSourceMap,
               }),
+
               // Don't consider CSS imports dead code even if the
               // containing package claims to have no side effects.
               // Remove this when webpack adds a warning or an error for this.
               // See https://github.com/webpack/webpack/issues/6571
               sideEffects: true,
             },
+
             // Adds support for CSS Modules (https://github.com/css-modules/css-modules)
             // using the extension .module.css
             {
@@ -413,6 +458,7 @@ module.exports = function(webpackEnv) {
                 getLocalIdent: getCSSModuleLocalIdent,
               }),
             },
+
             // Opt-in support for SASS (using .scss or .sass extensions).
             // By default we support SASS Modules with the
             // extensions .module.scss or .module.sass
@@ -426,12 +472,14 @@ module.exports = function(webpackEnv) {
                 },
                 'sass-loader'
               ),
+
               // Don't consider CSS imports dead code even if the
               // containing package claims to have no side effects.
               // Remove this when webpack adds a warning or an error for this.
               // See https://github.com/webpack/webpack/issues/6571
               sideEffects: true,
             },
+
             // Adds support for CSS Modules, but using SASS
             // using the extension .module.scss or .module.sass
             {
@@ -446,6 +494,7 @@ module.exports = function(webpackEnv) {
                 'sass-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.
@@ -453,6 +502,7 @@ module.exports = function(webpackEnv) {
             // that fall through the other loaders.
             {
               loader: require.resolve('file-loader'),
+
               // Exclude `js` files to keep "css" loader working as it injects
               // its runtime that would otherwise be processed through "file" loader.
               // Also exclude `html` and `json` extensions so they get processed
@@ -462,6 +512,7 @@ module.exports = function(webpackEnv) {
                 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.
           ],
@@ -469,6 +520,7 @@ module.exports = function(webpackEnv) {
       ],
     },
     plugins: [
+
       // Generates an `index.html` file with the <script> injected.
       new HtmlWebpackPlugin(
         Object.assign(
@@ -495,11 +547,13 @@ module.exports = function(webpackEnv) {
             : undefined
         )
       ),
+
       // Inlines the webpack runtime script. This script is too small to warrant
       // a network request.
       isEnvProduction &&
         shouldInlineRuntimeChunk &&
         new InlineChunkHtmlPlugin(HtmlWebpackPlugin, [ /runtime~.+[.]js/ ]),
+
       // 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">
@@ -507,21 +561,26 @@ module.exports = function(webpackEnv) {
       // in `package.json`, in which case it will be the pathname of that URL.
       // In development, this will be an empty string.
       new InterpolateHtmlPlugin(HtmlWebpackPlugin, env.raw),
+
       // This gives some necessary context to module not found errors, such as
       // the requesting resource.
       new ModuleNotFoundPlugin(paths.appPath),
+
       // 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 is set to production
       // during a production build.
       // Otherwise React will be compiled in the very slow development mode.
       new webpack.DefinePlugin(env.stringified),
+
       // This is necessary to emit hot updates (currently CSS only):
       isEnvDevelopment && 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/facebook/create-react-app/issues/240
       isEnvDevelopment && 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.
@@ -530,24 +589,28 @@ module.exports = function(webpackEnv) {
         new WatchMissingNodeModulesPlugin(paths.appNodeModules),
       isEnvProduction &&
         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,
+        publicPath,
       }),
+
       // 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$/, /moment$/),
+
       // Generate a service worker script that will precache, and keep up to date,
       // the HTML & assets that are part of the Webpack build.
       isEnvProduction &&
@@ -555,15 +618,18 @@ module.exports = function(webpackEnv) {
           clientsClaim: true,
           exclude: [ /\.map$/, /asset-manifest\.json$/ ],
           importWorkboxFrom: 'cdn',
-          navigateFallback: publicUrl + '/index.html',
+          navigateFallback: `${publicUrl}/index.html`,
           navigateFallbackBlacklist: [
+
             // Exclude URLs starting with /_, as they're likely an API call
             new RegExp('^/_'),
+
             // Exclude URLs containing a dot, as they're likely a resource in
             // public/ and not a SPA route
             new RegExp('/[^/]+\\.[^/]+$'),
           ],
         }),
+
       // TypeScript type checking
       useTypeScript &&
         new ForkTsCheckerWebpackPlugin({
@@ -594,6 +660,7 @@ module.exports = function(webpackEnv) {
           formatter: typescriptFormatter,
         }),
     ].filter(Boolean),
+
     // 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: {
@@ -603,6 +670,7 @@ module.exports = function(webpackEnv) {
       tls: 'empty',
       child_process: 'empty',
     },
+
     // Turn off performance processing because we utilize
     // our own hints via the FileSizeReporter
     performance: false,

config/webpackDevServer.config.js

@@ -1,17 +1,17 @@
-'use strict';
 
+const fs = require('fs');
 const errorOverlayMiddleware = require('react-dev-utils/errorOverlayMiddleware');
 const evalSourceMapMiddleware = require('react-dev-utils/evalSourceMapMiddleware');
 const noopServiceWorkerMiddleware = require('react-dev-utils/noopServiceWorkerMiddleware');
 const ignoredFiles = require('react-dev-utils/ignoredFiles');
 const paths = require('./paths');
-const fs = require('fs');
 
 const protocol = process.env.HTTPS === 'true' ? 'https' : 'http';
 const host = process.env.HOST || '0.0.0.0';
 
 module.exports = function(proxy, allowedHost) {
   return {
+
     // WebpackDevServer 2.4.3 introduced a security fix that prevents remote
     // websites from potentially accessing local content through DNS rebinding:
     // https://github.com/webpack/webpack-dev-server/issues/887
@@ -30,11 +30,14 @@ module.exports = function(proxy, allowedHost) {
     // really know what you're doing with a special environment variable.
     disableHostCheck:
       !proxy || process.env.DANGEROUSLY_DISABLE_HOST_CHECK === 'true',
+
     // Enable gzip compression of generated files.
     compress: true,
+
     // Silence WebpackDevServer's own logs since they're generally not useful.
     // It will still show compile warnings and errors with this setting.
     clientLogLevel: 'none',
+
     // By default WebpackDevServer serves physical files from current directory
     // in addition to all the virtual build products that it serves from memory.
     // This is confusing because those files won’t automatically be available in
@@ -50,20 +53,25 @@ module.exports = function(proxy, allowedHost) {
     // for some reason broken when imported through Webpack. If you just want to
     // use an image, put it in `src` and `import` it from JavaScript instead.
     contentBase: paths.appPublic,
+
     // By default files from `contentBase` will not trigger a page reload.
     watchContentBase: true,
+
     // Enable hot reloading server. It will provide /sockjs-node/ endpoint
     // for the WebpackDevServer client so it can learn when the files were
     // updated. The WebpackDevServer client is included as an entry point
     // in the Webpack development configuration. Note that only changes
     // to CSS are currently hot reloaded. JS changes will refresh the browser.
     hot: true,
+
     // It is important to tell WebpackDevServer to use the same "root" path
     // as we specified in the config. In development, we always serve from /.
     publicPath: '/',
+
     // WebpackDevServer is noisy by default so we emit custom message instead
     // by listening to the compiler events with `compiler.hooks[...].tap` calls above.
     quiet: true,
+
     // Reportedly, this avoids CPU overload on some systems.
     // https://github.com/facebook/create-react-app/issues/293
     // src/node_modules is not ignored to support absolute imports
@@ -71,11 +79,13 @@ module.exports = function(proxy, allowedHost) {
     watchOptions: {
       ignored: ignoredFiles(paths.appSrc),
     },
+
     // Enable HTTPS if the HTTPS environment variable is set to 'true'
     https: protocol === 'https',
     host,
     overlay: false,
     historyApiFallback: {
+
       // Paths with dots should still use the history fallback.
       // See https://github.com/facebook/create-react-app/issues/387.
       disableDotRule: true,
@@ -90,6 +100,7 @@ module.exports = function(proxy, allowedHost) {
 
       // This lets us fetch source contents from webpack for the error overlay
       app.use(evalSourceMapMiddleware(server));
+
       // This lets us open files from the runtime error overlay.
       app.use(errorOverlayMiddleware());
 

jest.config.js

@@ -8,29 +8,37 @@ module.exports = {
     '!src/**/provideServices.js',
     '!src/container/*.js',
   ],
+  resolver: 'jest-pnp-resolver',
   setupFiles: [
-    '<rootDir>/config/polyfills.js',
+    'react-app-polyfill/jsdom',
     '<rootDir>/config/setupEnzyme.js',
   ],
-  testMatch: [ '<rootDir>/test/**/*.test.{js,jsx,mjs}' ],
+  testMatch: [ '<rootDir>/test/**/*.test.{js,jsx,ts,tsx}' ],
-  testEnvironment: 'node',
+  testEnvironment: 'jsdom',
   testURL: 'http://localhost',
   transform: {
     '^.+\\.(js|jsx|mjs)$': '<rootDir>/node_modules/babel-jest',
     '^.+\\.css$': '<rootDir>/config/jest/cssTransform.js',
     '^(?!.*\\.(js|jsx|mjs|css|json)$)': '<rootDir>/config/jest/fileTransform.js',
   },
-  transformIgnorePatterns: [ '[/\\\\]node_modules[/\\\\].+\\.(js|jsx|mjs)$' ],
+  transformIgnorePatterns: [
+    '[/\\\\]node_modules[/\\\\].+\\.(js|jsx|ts|tsx)$',
+    '^.+\\.module\\.(css|sass|scss)$',
+  ],
   moduleNameMapper: {
     '^react-native$': 'react-native-web',
+    '^.+\\.module\\.(css|sass|scss)$': 'identity-obj-proxy',
   },
   moduleFileExtensions: [
     'web.js',
     'js',
+    'web.ts',
+    'ts',
+    'web.tsx',
+    'tsx',
     'json',
     'web.jsx',
     'jsx',
     'node',
-    'mjs',
   ],
 };

scripts/start.js

@@ -1,4 +1,4 @@
-'use strict';
+/* eslint-disable no-console */
 
 // Do this as the first thing so that any code reading it knows the right env.
 process.env.BABEL_ENV = 'development';
@@ -7,14 +7,13 @@ process.env.NODE_ENV = 'development';
 // Makes the script crash on unhandled rejections instead of silently
 // ignoring them. In the future, promise rejections that are not handled will
 // terminate the Node.js process with a non-zero exit code.
-process.on('unhandledRejection', err => {
+process.on('unhandledRejection', (err) => {
   throw err;
 });
 
 // Ensure environment variables are read.
 require('../config/env');
 
-
 const fs = require('fs');
 const chalk = require('chalk');
 const webpack = require('webpack');
@@ -28,6 +27,7 @@ const {
   prepareUrls,
 } = require('react-dev-utils/WebpackDevServerUtils');
 const openBrowser = require('react-dev-utils/openBrowser');
+const { checkBrowsers } = require('react-dev-utils/browsersHelper');
 const paths = require('../config/paths');
 const configFactory = require('../config/webpack.config');
 const createDevServerConfig = require('../config/webpackDevServer.config');
@@ -41,7 +41,8 @@ if (!checkRequiredFiles([paths.appHtml, paths.appIndexJs])) {
 }
 
 // Tools like Cloud9 rely on this.
-const DEFAULT_PORT = parseInt(process.env.PORT, 10) || 3000;
+const DEFAULT_PORT = 3000;
+const PORT = parseInt(process.env.PORT) || DEFAULT_PORT;
 const HOST = process.env.HOST || '0.0.0.0';
 
 if (process.env.HOST) {
@@ -53,7 +54,7 @@ if (process.env.HOST) {
     )
   );
   console.log(
-    `If this was unintentional, check that you haven't mistakenly set it in your shell.`
+    'If this was unintentional, check that you haven\'t mistakenly set it in your shell.'
   );
   console.log(
     `Learn more here: ${chalk.yellow('http://bit.ly/CRA-advanced-config')}`
@@ -61,57 +62,64 @@ if (process.env.HOST) {
   console.log();
 }
 
-// We require that you explictly set browsers and do not fall back to
-// browserslist defaults.
-const { checkBrowsers } = require('react-dev-utils/browsersHelper');
 checkBrowsers(paths.appPath, isInteractive)
-  .then(() => {
+  .then(() =>
+
     // We attempt to use the default port but if it is busy, we offer the user to
     // run on a different port. `choosePort()` Promise resolves to the next free port.
-    return choosePort(HOST, DEFAULT_PORT);
+    choosePort(HOST, PORT))
-  })
+  .then((port) => {
-  .then(port => {
+    if (port === null) {
-    if (port == null) {
       // We have not found a port.
       return;
     }
+
     const config = configFactory('development');
     const protocol = process.env.HTTPS === 'true' ? 'https' : 'http';
     const appName = require(paths.appPackageJson).name;
+
     const urls = prepareUrls(protocol, HOST, port);
+
     // Create a webpack compiler that is configured with custom messages.
     const compiler = createCompiler(webpack, config, appName, urls, useYarn);
+
     // Load proxy config
     const proxySetting = require(paths.appPackageJson).proxy;
+
     const proxyConfig = prepareProxy(proxySetting, paths.appPublic);
+
     // Serve webpack assets generated by the compiler over a web server.
     const serverConfig = createDevServerConfig(
       proxyConfig,
       urls.lanUrlForConfig
     );
     const devServer = new WebpackDevServer(compiler, serverConfig);
+
     // Launch WebpackDevServer.
-    devServer.listen(port, HOST, err => {
+    devServer.listen(port, HOST, (err) => {
       if (err) {
         return console.log(err);
       }
       if (isInteractive) {
         clearConsole();
       }
+
       console.log(chalk.cyan('Starting the development server...\n'));
-      openBrowser(urls.localUrlForBrowser);
+
+      return openBrowser(urls.localUrlForBrowser);
     });
 
-    ['SIGINT', 'SIGTERM'].forEach(function(sig) {
+    [ 'SIGINT', 'SIGTERM' ].forEach((sig) => {
-      process.on(sig, function() {
+      process.on(sig, () => {
         devServer.close();
         process.exit();
       });
     });
   })
-  .catch(err => {
+  .catch((err) => {
     if (err && err.message) {
       console.log(err.message);
     }
+
     process.exit(1);
   });

test/utils/DateInput.test.js

@@ -1,6 +1,6 @@
 import React from 'react';
 import { shallow } from 'enzyme';
-import FontAwesomeIcon from '@fortawesome/react-fontawesome';
+import { FontAwesomeIcon } from '@fortawesome/react-fontawesome';
 import moment from 'moment';
 import DateInput from '../../src/utils/DateInput';
 

test/utils/SortingDropdown.test.js

@@ -2,7 +2,7 @@ import React from 'react';
 import { shallow } from 'enzyme';
 import { DropdownItem } from 'reactstrap';
 import { identity, values } from 'ramda';
-import FontAwesomeIcon from '@fortawesome/react-fontawesome';
+import { FontAwesomeIcon } from '@fortawesome/react-fontawesome';
 import caretDownIcon from '@fortawesome/fontawesome-free-solid/faSortAmountDown';
 import * as sinon from 'sinon';
 import SortingDropdown from '../../src/utils/SortingDropdown';