chore: updates

Author: JoviDeCroock

packages/babel-preset-react-app/create.js

@@ -54,6 +54,11 @@ module.exports = function(api, opts, env) {
   // We should be able to provide a babelconfig for every build.
   // Does this mean we should move this to webpack or specify some BABEL_ENV?
   var isModern = validateBoolOption('modern', opts.modern, false);
+  var shouldBuildModern = validateBoolOption(
+    'shouldBuildModernAndLegacy',
+    opts.shouldBuildModernAndLegacy,
+    true
+  );
 
   var absoluteRuntimePath = undefined;
   if (useAbsoluteRuntime) {
@@ -89,13 +94,17 @@ module.exports = function(api, opts, env) {
         {
           // We want Create React App to be IE 9 compatible until React itself
           // no longer works with IE 9
-          targets: isModern ? modernTargets : legacyTargets,
+          targets: shouldBuildModern
+            ? isModern
+              ? modernTargets
+              : legacyTargets
+            : undefined,
           // Users cannot override this behavior because this Babel
           // configuration is highly tuned for ES5 support
           ignoreBrowserslistConfig: true,
           // If users import all core-js they're probably not concerned with
           // bundle size. We shouldn't rely on magic to try and shrink it.
-          useBuiltIns: isModern ? 'entry' : false,
+          useBuiltIns: !isModern || !shouldBuildModern ? false : 'entry',
           // Do not transform modules to CJS
           modules: false,
           // Exclude transforms that make all code slower

packages/create-react-app/createReactApp.js

@@ -77,6 +77,7 @@ const program = new commander.Command(packageJson.name)
   )
   .option('--use-npm')
   .option('--use-pnp')
+  .option('--modern')
   .option('--typescript')
   .allowUnknownOption()
   .on('--help', () => {

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

@@ -31,11 +31,10 @@ const getClientEnvironment = require('./env');
 const ModuleNotFoundPlugin = require('react-dev-utils/ModuleNotFoundPlugin');
 const ForkTsCheckerWebpackPlugin = require('react-dev-utils/ForkTsCheckerWebpackPlugin');
 const typescriptFormatter = require('react-dev-utils/typescriptFormatter');
-// const HtmlWebpackEsmodulesPlugin = require('react-dev-utils/html-webpack-esmodules-plugin');
+const HtmlWebpackEsmodulesPlugin = require('react-dev-utils/html-webpack-esmodules-plugin');
 // @remove-on-eject-begin
 const getCacheIdentifier = require('react-dev-utils/getCacheIdentifier');
 // @remove-on-eject-end
-const HtmlWebpackEsmodulesPlugin = require('./webpack/html-webpack-esmodules-plugin');
 
 // Source maps are resource heavy and can cause out of memory issue for large source files.
 const shouldUseSourceMap = process.env.GENERATE_SOURCEMAP !== 'false';
@@ -365,7 +364,7 @@ module.exports = function(
                 presets: [
                   [
                     require.resolve('babel-preset-react-app'),
-                    { modern: isModernOutput },
+                    { modern: isModernOutput, shouldBuildModernAndLegacy },
                   ],
                 ],
                 // Make sure we have a unique cache identifier, erring on the

packages/react-scripts/config/webpack/html-webpack-esmodules-plugin.js

@@ -63,7 +63,7 @@ if (!checkRequiredFiles([paths.appHtml, paths.appIndexJs])) {
 // Process CLI arguments
 const argv = process.argv.slice(2);
 const writeStatsJson = argv.indexOf('--stats') !== -1;
-const buildModern = argv.indexOf('--legacy') === -1;
+const buildModern = argv.indexOf('--modern') !== -1;
 
 // Generate configuration
 const modernConfig = configFactory('production', {