Support @babel/polyfill in entry point

docusaurus/docs/supported-browsers-features.md

@@ -6,7 +6,7 @@ sidebar_label: Supported Browsers and Features
 
 ## Supported Browsers
 
-By default, the generated project supports all modern browsers. Support for Internet Explorer 9, 10, and 11 requires [polyfills](https://github.com/facebook/create-react-app/blob/master/packages/react-app-polyfill/README.md).
+By default, the generated project supports all modern browsers. Support for Internet Explorer 9, 10, and 11 requires polyfills. For a minimum set of polyfills to support older browsers, use [react-app-polyfill](https://github.com/facebook/create-react-app/blob/master/packages/react-app-polyfill/README.md). To polyfill other language features, see the [Adding Polyfills](#adding-polyfills) section below
 
 ## Supported Language Features
 
@@ -27,7 +27,11 @@ Note that **this project includes no [polyfills](https://github.com/facebook/cre
 
 If you use any other ES6+ features that need **runtime support** (such as `Array.from()` or `Symbol`), make sure you are [including the appropriate polyfills manually](https://github.com/facebook/create-react-app/blob/master/packages/react-app-polyfill/README.md), or that the browsers you are targeting already support them.
 
-## Configuring supported browsers
+## Adding Polyfills
+
+You can install [`@babel/polyfill`](https://babeljs.io/docs/en/babel-polyfill) as a dependency in your application, and import it at the very top of your app's entry point (`src/index.js` or `src/index.tsx`) to emulate a full ES2015+ environment. Your `browerslist` configuration will be used to only include the polyfills necessary by your target browsers.
+
+## Configuring Supported Browsers
 
 By default, the generated project includes a set of [`browerslist`](https://github.com/browserslist/browserslist) configuration in your `package.json` file to target a broad range of browsers based on global usage (`> 0.2%`) during production builds, and modern browers during development. This gives a good development experience, especially when using langauge features such as async/await, but still provides high compatibility with many browsers in production.
 

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

@@ -79,9 +79,8 @@ module.exports = function(api, opts, env) {
         // Latest stable ECMAScript features
         require('@babel/preset-env').default,
         {
-          // 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: false,
+          // Allow importing @babel/polyfill in entrypoint and use browserlist to select polyfills
+          useBuiltIns: 'entry',
           // Do not transform modules to CJS
           modules: false,
           // Exclude transforms that make all code slower