app.tsx

import * as React from 'react';
import * as ReactDOM from 'react-dom';

import withBlueBackground from './withBlueBackground';
import Hello from './Hello';

const BlueHello = withBlueBackground(Hello);
ReactDOM.render(
  <BlueHello name="Bob" style={{ fontWeight: 'bold' }} />,
  document.getElementById('app')
);