ReactJS: Uncaught ReferenceError: Set is not defined

Question

On some browsers only i get the

Uncaught ReferenceError: Set is not defined.

It is reactjs app created with create-react-app.

Why do i still get the error?
How do i use polyfill?
Does not reactjs use polyfill by default?

webpack.config.prod.js

entry: [require.resolve('./polyfills'), paths.appIndexJs],

polyfills.js

'use strict';

if (typeof Promise === 'undefined') {
  // Rejection tracking prevents a common issue where React gets into an
  // inconsistent state due to an error, but it gets swallowed by a Promise,
  // and the user has no idea what causes React's erratic future behavior.
  require('promise/lib/rejection-tracking').enable();
  window.Promise = require('promise/lib/es6-extensions.js');
}

// fetch() polyfill for making API calls.
require('whatwg-fetch');

// Object.assign() is commonly used with React.
// It will use the native implementation if it's present and isn't buggy.
Object.assign = require('object-assign');

// In tests, polyfill requestAnimationFrame since jsdom doesn't provide it yet.
// We don't polyfill it in the browser--this is user's responsibility.
if (process.env.NODE_ENV === 'test') {
  require('raf').polyfill(global);
}

Answer 1

No sure whether anyone found the right solution. However for older browser especially on Android Kitkat 4.4 browsers/webview this problem is very evident. Please use the following link for the solution

https://reactjs.org/docs/javascript-environment-requirements.html

If you are using ReactJS 16 then first include the babel-polyfill

• npm install --save babel-polyfill

Open your index.js and import the babel-polyfill

• import 'babel-polyfill'

Create a build and deploy. This should solve the issue.