webpack.config.dev.js

"use strict";

const path = require("path");
const webpack = require("webpack");
const ExtractTextPlugin = require("extract-text-webpack-plugin");
const FriendlyErrorsWebpackPlugin = require("friendly-errors-webpack-plugin");
const WatchMissingNodeModulesPlugin = require("react-dev-utils/WatchMissingNodeModulesPlugin");
const PrettierPlugin = require("prettier-webpack-plugin");
const ResolveEntryModulesPlugin = require("resolve-entry-modules-webpack-plugin");
const atImport = require("postcss-import");
const postcssURL = require("postcss-url");
const cssNext = require("postcss-cssnext");
const getClientEnvironment = require("./env");
const paths = require("./paths");

// Webpack uses `publicPath` to determine where the app is being served from.
// In development, we serve from the full domain we’re booting the app on.
const protocol = process.env.ASSETS_HTTPS === "true" ? "https" : "http";
const host = process.env.ASSETS_HOST || "localhost";
const port = parseInt(process.env.ASSETS_PORT, 10) || 8080;
const serverBase = `${protocol}://${host}:${port}`;
const publicPath = `${serverBase}${paths.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 === "./";
// Get environment variables to inject into our app.
const env = getClientEnvironment();

// 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 = shouldUseRelativeAssetPaths
  ? // Making sure that the publicPath goes back to to build folder.
    { publicPath: Array(cssFilename.split("/").length).join("../") }
  : {};

// 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",
  // Specify the context we expect app code to be loaded from
  context: paths.appSrc,
  // These are the "entry points" to our application.
  // This means they will be the "root" imports that are included in JS bundle.
  // We can have multiple entries and so we merge them with some common values to
  // enable "hot" CSS and auto-refreshes for JS.
  entry: paths.appEntries.reduce((output, entry) => {
    const [name, location] = entry;
    // If the entry name begins with `inline` we consider it inline
    const inline = /__inline/.test(name);
    // Test env?
    const testEnv = process.env.ASSETS_ENV && process.env.ASSETS_ENV === "test"
    // Build up the definition for each entry
    let entryDefinition = [];
    // Skip hot-reload and other unnecessary things for "inline" assets
    if (!inline && !testEnv) {
      entryDefinition = entryDefinition.concat([
        // Add our custom dev niceties:
        // - Supressing the output of the webpack-dev-server and hot-module-resolveLoader
        //   in the console. No more [WDS] and [MHR] messages.
        // - Automatically reloading extracted CSS
        require.resolve("./devNiceties"),
        // 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.
        // the line below with these two lines if you prefer the stock client:
        require.resolve("webpack-dev-server/client") + `?${serverBase}`,
        // Disabled until the ExtractText plugin supports HMR
        // https://github.com/webpack-contrib/extract-text-webpack-plugin/issues/592
        // require.resolve("webpack/hot/dev-server")
      ]);
    }
    // Add these for all entries
    entryDefinition = entryDefinition.concat([
      // We ship a few polyfills by default:
      require.resolve("./polyfills"),
      // Finally, this is where the code lives for this entry
      location
      // 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[name] = entryDefinition;
    return output;
  }, {}),
  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 real files. It's just the virtual path that is
    // served by WebpackDevServer in development.
    filename: "[name].js",
    chunkFilename: "chunk.[name].js",
    // This is the URL that app is served from. We use "/" in development.
    publicPath: publicPath
  },
  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"]
      .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"]
  },
  // Resolve loaders (webpack plugins for CSS, images, transpilation) from the
  // directory of `react-scripts` itself rather than the project directory.
  resolveLoader: {
    modules: [paths.ownNodeModules, paths.appNodeModules]
  },
  module: {
    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)$/,
        enforce: "pre",
        use: [
          {
            // Point ESLint to our predefined config.
            options: {
              configFile: path.join(__dirname, "../eslintrc"),
              useEslintrc: false,
              // Automatically fix eslint-issues (i.e., run through prettier)
              fix: true
            },
            loader: "eslint-loader"
          }
        ],
        include: paths.appSrc
      },
      // ** ADDING/UPDATING LOADERS **
      // The "url" 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 "url" 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$/, /\.json$/],
        use: [
          {
            loader: "file-loader",
            options: {
              name: "[path][name].[ext]"
            }
          }
        ]
      },
      // Process JS with Babel.
      {
        test: /\.(js|jsx)$/,
        include: paths.appSrc,
        use: [
          {
            loader: "babel-loader",
            options: {
              babelrc: true,
              presets: [require.resolve("babel-preset-react-app")],
              // This is a feature of `babel-loader` for webpack (not Babel itself).
              // It enables caching results in ./node_modules/.cache/babel-loader/
              // directory for faster rebuilds.
              cacheDirectory: true
            }
          }
        ]
      },
      // The notation here is somewhat confusing.
      // "postcss" loader applies autoprefixer to our CSS.
      // "css" loader resolves paths in CSS and adds assets as dependencies.
      // "style" loader normally turns CSS into JS modules injecting <style>,
      // but unlike in development configuration, we do something different.
      // `ExtractTextPlugin` first applies the "postcss" and "css" loaders
      // (second argument), then grabs the result CSS and puts it into a
      // separate file in our build process. This way we actually ship
      // a single CSS file in production instead of JS code injecting <style>
      // tags. If you use code splitting, however, any async bundles will still
      // use the "style" loader inside the async code so CSS from them won't be
      // in the main CSS file.
      {
        test: /\.css$/,
        // Note: this won't work without `new ExtractTextPlugin()` in `plugins`.
        use: ExtractTextPlugin.extract(
          Object.assign(
            {
              fallback: "style-loader",
              use: [
                {
                  loader: "css-loader",
                  options: {
                    importLoaders: 1
                  }
                },
                {
                  loader: "postcss-loader",
                  options: {
                    ident: "postcss", // https://webpack.js.org/guides/migrating/#complex-options
                    plugins: () => [
                      // Add module-like @import support to our CSS. This sets the context for all imports
                      // to be the base entry point.
                      atImport(),
                      // postcss-url "rebases" any `url()` references in CSS to their original relative
                      // position on the filesystem (so that postcss-import doesn't break things)
                      postcssURL(),
                      // cssnext gives us compilation of future-CSS syntax, it also includes autoprefixer
                      // so we don't need to add that separately.
                      cssNext({
                        browsers: [
                          ">1%",
                          "last 4 versions",
                          "Firefox ESR",
                          "not ie < 9" // React doesn't support IE8 anyway
                        ],
                        features: {
                          customProperties: {
                            warnings: false
                          }
                        },
                      })
                    ]
                  }
                }
              ]
            },
            extractTextPluginOptions
          )
        )
      }
      // ** STOP ** Are you adding a new loader?
      // Remember to add the new extension(s) to the "url" loader exclusion list.
    ]
  },
  plugins: [
    // Friendlier error messages
    new FriendlyErrorsWebpackPlugin(),
    // 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),
    // Expose each entry as a resolution point so that we can resolve from the
    // root of each entry point and avoid relative requires
    new ResolveEntryModulesPlugin(),
    // This is necessary to emit hot updates (currently CSS only):
    // Disabled until the ExtractText plugin supports HMR
    // https://github.com/webpack-contrib/extract-text-webpack-plugin/issues/592
    // new webpack.HotModuleReplacementPlugin(),
    // Format CSS with Prettier. JS is handled through the eslint-loader
    // (so that we can mix in other eslint configuration)
    new PrettierPlugin({
      parser: "css",
      extensions: [".css"]
    }),
    // Note: this won't work without ExtractTextPlugin.extract(..) in `loaders`.
    new ExtractTextPlugin({
      filename: "[name].css"
    }),
    // 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)
  ],
  // 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
  }
};