React hot loader v3

index.jsx

import { AppContainer } from 'react-hot-loader'
import { render } from 'react-dom'
import App from './app'

const renderApp = (Root) => (
  render(
    <AppContainer>
      <Root />
    </AppContainer>,
    document.getElementById('app-root')
  )
)

renderApp(App)

if (module.hot) {
  module.hot.accept('./app', () => {
    const NewApp = require('./app').default
    renderApp(NewApp)
  })
}