create-react-app
Manual import from core-js:
core-js
Create a file called (something like) polyfills.js and import it into root index.js file. Run npm install core-js or yarn add core-js and import your specific required features.
polyfills.js
index.js
npm install core-js
yarn add core-js
import 'core-js/fn/array/find' import 'core-js/fn/array/includes' import 'core-js/fn/number/is-nan'
Using Polyfill service:
Use the polyfill.io CDN to retrieve custom, browser-specific polyfills by adding this line to index.html:
index.html
<script src='https://cdn.polyfill.io/v2/polyfill.min.js?features=default,Array.prototype.includes'></script>
In the above script we had to explicitly request the Array.prototype.includes feature as it is not included in the default feature set.
Array.prototype.includes