stateful functional component

App.js

import React, { useState } from 'react';
import './App.css';

function App() {
  const [color, changeColor] = useState('blue');

  return (
    <div className="App">
      <button onClick={changeColor.bind(null, 'blue')}>blue</button>
      <button onClick={changeColor.bind(null, 'green')}>green</button>
      <button onClick={changeColor.bind(null, 'red')}>red</button>

      <div className={`box ${color}`}>
        Lorem Ipsum
      </div>
    </div>
  );
}

export default App;