text: 'use strict';
  
  const autoprefixer = require('autoprefixer');
  const path = require('path');
  const webpack = require('webpack');
  const HtmlWebpackPlugin = require('html-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 eslintFormatter = require('react-dev-utils/eslintFormatter');
  const ModuleScopePlugin = require('react-dev-utils/ModuleScopePlugin');
  const getClientEnvironment = require('./env');
  const paths = require('./paths');
  const OfflinePlugin = require('offline-plugin');
  
  // Webpack uses `publicPath` to determine where the app is being served from.
  // In development, we always serve from the root. This makes config easier.
  const publicPath = '/';
  // `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 = '';
  // Get environment variables to inject into our app.
  const env = getClientEnvironment(publicUrl);
  
  // This is the development configuration.
  // It is focused on developer experience and fast rebuilds.
  // The production configuration is different and lives in a separate file.
  module.exports = {
      // 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: '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: [
          // 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'),
          require.resolve('react-hot-loader/patch'),
          require.resolve('react-dev-utils/webpackHotDevClient'),
          // We ship a few polyfills by default:
          require.resolve('./polyfills'),
          // Errors should be considered fatal in development
          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: {
          // Next line is not used in dev but WebpackDevServer crashes without it:
          path: paths.appBuild,
          // Add /* filename */ comments to generated require()s in the output.
          pathinfo: true,
          // 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.
          filename: 'static/js/bundle.js',
          // There are also additional JS chunk files if you use code splitting.
          chunkFilename: '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 =>
              path.resolve(info.absoluteResourcePath),
      },
      resolve: {
          // This allows you to set a fallback for where Webpack should look for modules.
          // We read `NODE_PATH` environment variable in `paths.js` and pass paths here.
          // 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(paths.nodePaths),
          // 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: {
          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 } },
  
              // ** 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$/,
                      /\.scss$/,
                      /\.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: {
                      // 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,
                  },
              },
              // "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|scss)$/,
                  use: [
                      require.resolve('style-loader'),
                      {
                          loader: require.resolve('css-loader'),
                          options: {
                              modules: true,
                              localIdentName: '[name]__[local]___[hash:base64:5]',
                              importLoaders: 1,
                          },
                      },
                      {
                          loader: require.resolve('postcss-loader'),
                          options: {
                              ident: 'postcss', // https://webpack.js.org/guides/migrating/#complex-options
                              plugins: () => [
                                  require('postcss-flexbugs-fixes'),
                                  autoprefixer({
                                      browsers: [
                                          '>1%',
                                          'last 4 versions',
                                          'Firefox ESR',
                                          'not ie < 9', // React doesn't support IE8 anyway
                                      ],
                                      flexbox: 'no-2009',
                                  }),
                              ],
                          },
                      },
                      require.resolve('sass-loader'),
                  ],
              },
              // ** STOP ** Are you adding a new loader?
              // Remember to add the new extension(s) to the "file" loader exclusion list.
          ],
      },
      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 development, this will be an empty string.
          new InterpolateHtmlPlugin(env.raw),
          // Generates an `index.html` file with the <script> injected.
          new HtmlWebpackPlugin({
              inject: true,
              template: paths.appHtml,
          }),
          // 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),
          // 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),
          // 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: {
          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: {
          hints: false,
      },
  };
  