HMR for create-react-app

index.js

import React from 'react';
import ReactDOM from 'react-dom';
import App from './App';
import './index.css';
const rootEl = document.getElementById('root');

ReactDOM.render(
    <App />,
  rootEl
);

if (module.hot) {
  module.hot.accept('./App', () => {
    const NextApp = require('./App').default;
    ReactDOM.render(
      <NextApp />,
      rootEl
    );
  });
}