[18] Update browser requirements (#4476)

* [18] Update browser requirements

* Update based on feedback

Author: rickhanlonii

content/docs/reference-javascript-environment-requirements.md

@@ -6,24 +6,13 @@ category: Reference
 permalink: docs/javascript-environment-requirements.html
 ---
 
-React 16 depends on the collection types [Map](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map) and [Set](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set). If you support older browsers and devices which may not yet provide these natively (e.g. IE < 11) or which have non-compliant implementations (e.g. IE 11), consider including a global polyfill in your bundled application, such as [core-js](https://github.com/zloirock/core-js).
+React 18 supports all modern browsers (Edge, Firefox, Chrome, Safari, etc).
 
-A polyfilled environment for React 16 using core-js to support older browsers might look like:
+If you support older browsers and devices such as Internet Explorer which do not provide modern browser features natively or have non-compliant implementations, consider including a global polyfill in your bundled application.
 
-```js
-import 'core-js/es/map';
-import 'core-js/es/set';
+Here is a list of the modern features React 18 uses:
+- [`Promise`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise)
+- [`Symbol`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol)
+- [`Object.assign`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/assign)
 
-import React from 'react';
-import ReactDOM from 'react-dom/client';
-
-const root = ReactDOM.createRoot(document.getElementById('root'));
-root.render(<h1>Hello, world!</h1>);
-```
-
-React also depends on `requestAnimationFrame` (even in test environments).  
-You can use the [raf](https://www.npmjs.com/package/raf) package to shim `requestAnimationFrame`:
-
-```js
-import 'raf/polyfill';
-```
+The correct polyfill for these features depend on your environment. For many users, you can configure your [Browserlist](https://github.com/browserslist/browserslist) settings. For others, you may need to import polyfills like [`core-js`](https://github.com/zloirock/core-js) directly.