react-app-polyfill

What is react-app-polyfill?

The react-app-polyfill package provides a set of polyfills necessary for a React application to run on older browsers. It includes polyfills for features like Promises, fetch, and other ES6+ features not supported in older browsers.

What are react-app-polyfill's main functionalities?

IE 9 Support

This feature includes polyfills for IE9 compatibility, ensuring that features like Array.prototype methods and requestAnimationFrame are supported.

import 'react-app-polyfill/ie9';

IE 11 Support

This feature includes polyfills for IE11 compatibility, providing support for ES6 features not available in IE11.

import 'react-app-polyfill/ie11';

Stable Features Support

This feature includes polyfills for stable language features that are widely adopted by most modern browsers but may be missing in some older versions.

import 'react-app-polyfill/stable';

Other packages similar to react-app-polyfill

core-js

Core-js is a modular standard library for JavaScript, which includes polyfills for ECMAScript up to 2021. It's more comprehensive than react-app-polyfill but requires manual configuration for specific features.

babel-polyfill

Babel-polyfill is now deprecated in favor of core-js and regenerator-runtime. It used to provide a smoother development experience by emulating a full ES2015+ environment.

es6-shim

Es6-shim is a shim for legacy JavaScript engines to support ES6 features. It's similar to react-app-polyfill but does not tailor specifically to React applications.

README

react-app-polyfill

This package includes polyfills for various browsers. It includes minimum requirements and commonly used language features used by Create React App projects.

Usage

First, install the package using Yarn or npm:

npm install react-app-polyfill

or

yarn add react-app-polyfill

Supporting Internet Explorer

You can import the entry point for the minimal version you intend to support to ensure that the minimum language features are present that are required to use Create React App. For example, if you import the IE9 entry point, this will include IE10 and IE11 support.

These modules ensure the following language features are present:

1. Promise (for async / await support)
2. window.fetch (a Promise-based way to make web requests in the browser)
3. Object.assign (a helper required for Object Spread, i.e. { ...a, ...b })
4. Symbol (a built-in object used by for...of syntax and friends)
5. Array.from (a built-in static method used by array spread, i.e. [...arr])

If you need more features, see the Polyfilling other language features section below.

Internet Explorer 9

// This must be the first line in src/index.js
import 'react-app-polyfill/ie9';

// ...

Internet Explorer 11

// This must be the first line in src/index.js
import 'react-app-polyfill/ie11';

// ...

Polyfilling other language features

You can also polyfill stable language features not available in your target browsers. If you're using this in Create React App, it will automatically use the browserslist you've defined to only include polyfills needed by your target browsers when importing the stable polyfill. Make sure to follow the Internet Explorer steps above if you need to support Internet Explorer in your application.

// This must be the first line in src/index.js
import 'react-app-polyfill/stable';

// ...

If you are supporting Internet Explorer 9 or Internet Explorer 11 you should include both the ie9 or ie11 and stable modules:

For IE9:

// These must be the first lines in src/index.js
import 'react-app-polyfill/ie9';
import 'react-app-polyfill/stable';

// ...

For IE11:

// These must be the first lines in src/index.js
import 'react-app-polyfill/ie11';
import 'react-app-polyfill/stable';

// ...