Multicompilation of indexXX.js files to indexXX.html outputs

packages/react-scripts/config/webpack.config.dev.js

@@ -35,7 +35,9 @@ 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 = {
+const configure = indexName => ({
+  // Name in compilation output log when multiple entry files are used.
+  name: `${indexName}.html`,
   // You may want 'eval' instead if you prefer to see the compiled output in DevTools.
   // See the discussion in https://github.com/facebookincubator/create-react-app/issues/343.
   devtool: 'cheap-module-source-map',
@@ -58,8 +60,8 @@ module.exports = {
     require.resolve('./polyfills'),
     // Errors should be considered fatal in development
     require.resolve('react-error-overlay'),
-    // Finally, this is your app's code:
-    paths.appIndexJs,
+    // Finally, this is your app's code, depending on entry index file:
+    paths.appIndexJs.replace('index', indexName),
     // We include the app code last so that if there is a runtime error during
     // initialization, it doesn't blow up the WebpackDevServer client, and
     // changing JS code would still trigger a refresh.
@@ -72,9 +74,13 @@ module.exports = {
     // This does not produce a real file. It's just the virtual path that is
     // served by WebpackDevServer in development. This is the JS bundle
     // containing code from all our entry points, and the Webpack runtime.
-    filename: 'static/js/bundle.js',
+    filename: indexName === 'index'
+      ? 'static/js/bundle.js'
+      : `static/js/${indexName}-bundle.js`,
     // There are also additional JS chunk files if you use code splitting.
-    chunkFilename: 'static/js/[name].chunk.js',
+    chunkFilename: indexName === 'index'
+      ? 'static/js/[name].chunk.js'
+      : `static/js/${indexName}-[name].chunk.js`,
     // This is the URL that app is served from. We use "/" in development.
     publicPath: publicPath,
     // Point sourcemap entries to original disk location
@@ -246,6 +252,7 @@ module.exports = {
     new InterpolateHtmlPlugin(env.raw),
     // Generates an `index.html` file with the <script> injected.
     new HtmlWebpackPlugin({
+      filename: `${indexName}.html`,
       inject: true,
       template: paths.appHtml,
     }),
@@ -285,4 +292,16 @@ module.exports = {
   performance: {
     hints: false,
   },
-};
+});
+
+// Read potential indexXX.js candidates from src/ at this point.
+const fs = require('fs');
+const indexFiles = fs.readdirSync(paths.appSrc).filter(file => {
+  // Takes all indexXX.js files. Does not check validity at this point, could be a directory and crash.
+  return path.basename(file).startsWith('index') &&
+    path.extname(file) === '.js';
+});
+
+// Returns an array of configurations to trigger webpack multicompilation
+module.exports = indexFiles.map(indexFile =>
+  configure(path.parse(indexFile).name));

packages/react-scripts/config/webpack.config.prod.js

@@ -57,14 +57,19 @@ const extractTextPluginOptions = shouldUseRelativeAssetPaths
 // 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 = {
+const configure = indexName => ({
+  // Name in compilation output log when multiple entry files are used.
+  name: `${indexName}.html`,
   // Don't attempt to continue if there are any errors.
   bail: true,
   // We generate sourcemaps in production. This is slow but gives good results.
   // You can exclude the *.map files from the build during deployment.
   devtool: 'source-map',
   // In production, we only want to load the polyfills and the app code.
-  entry: [require.resolve('./polyfills'), paths.appIndexJs],
+  entry: [
+    require.resolve('./polyfills'),
+    paths.appIndexJs.replace('index', indexName),
+  ],
   output: {
     // The build folder.
     path: paths.appBuild,
@@ -258,6 +263,7 @@ module.exports = {
     new InterpolateHtmlPlugin(env.raw),
     // Generates an `index.html` file with the <script> injected.
     new HtmlWebpackPlugin({
+      filename: `${indexName}.html`,
       inject: true,
       template: paths.appHtml,
       minify: {
@@ -301,7 +307,9 @@ module.exports = {
     // to their corresponding output file so that tools can pick it up without
     // having to parse `index.html`.
     new ManifestPlugin({
-      fileName: 'asset-manifest.json',
+      fileName: indexName === 'index'
+        ? 'asset-manifest.json'
+        : `${indexName}-asset-manifest.json`,
     }),
     // Generate a service worker script that will precache, and keep up to date,
     // the HTML & assets that are part of the Webpack build.
@@ -311,7 +319,9 @@ module.exports = {
       // If a URL is already hashed by Webpack, then there is no concern
       // about it being stale, and the cache-busting can be skipped.
       dontCacheBustUrlsMatching: /\.\w{8}\./,
-      filename: 'service-worker.js',
+      fileName: indexName === 'index'
+        ? 'service-worker.js'
+        : `${indexName}-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.
@@ -321,7 +331,7 @@ module.exports = {
       },
       minify: true,
       // For unknown URLs, fallback to the index page
-      navigateFallback: publicUrl + '/index.html',
+      navigateFallback: `${publicUrl}/${indexName}.html`,
       // Ignores URLs starting from /__ (useful for Firebase):
       // https://github.com/facebookincubator/create-react-app/issues/2237#issuecomment-302693219
       navigateFallbackWhitelist: [/^(?!\/__).*/],
@@ -345,4 +355,16 @@ module.exports = {
     net: 'empty',
     tls: 'empty',
   },
-};
+});
+
+// Read potential indexXX.js candidates from src/ at this point.
+const fs = require('fs');
+const indexFiles = fs.readdirSync(paths.appSrc).filter(file => {
+  // Takes all indexXX.js files. Does not check validity at this point, could be a directory and crash.
+  return path.basename(file).startsWith('index') &&
+    path.extname(file) === '.js';
+});
+
+// Returns an array of configurations to trigger webpack multicompilation
+module.exports = indexFiles.map(indexFile =>
+  configure(path.parse(indexFile).name));

packages/react-scripts/config/webpackDevServer.config.js

@@ -68,7 +68,7 @@ module.exports = function(proxy, allowedHost) {
     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: config.output.publicPath,
+    publicPath: (config[0] || config).output.publicPath,
     // WebpackDevServer is noisy by default so we emit custom message instead
     // by listening to the compiler events with `compiler.plugin` calls above.
     quiet: true,

packages/react-scripts/scripts/build.js

@@ -76,12 +76,16 @@ measureFileSizesBeforeBuild(paths.appBuild)
       }
 
       console.log('File sizes after gzip:\n');
-      printFileSizesAfterBuild(stats, previousFileSizes, paths.appBuild);
+      // Webpack multicompilation produces an array of stats
+      (stats.stats || [stats]).forEach(stats => {
+        console.log(`  ${stats.compilation.name}:`);
+        printFileSizesAfterBuild(stats, previousFileSizes, paths.appBuild);
+      });
       console.log();
 
       const appPackage = require(paths.appPackageJson);
       const publicUrl = paths.publicUrl;
-      const publicPath = config.output.publicPath;
+      const publicPath = (config[0] || config).output.publicPath;
       const buildFolder = path.relative(process.cwd(), paths.appBuild);
       printHostingInstructions(
         appPackage,