用ts重写React官方文档里的demo（1）——使用State Hook/使用Effect Hook

import React, { useState, useEffect } from 'react';

function Click() {
  const [count, setCount] = useState(0);

  // 相当于 componentDidMount 和 componentDidUpdate
  useEffect(() => {
    document.title = `You clicked  ${count} times`;
  });
  return (
    <div>
      <p>You clicked {count} times</p>
      <button onClick={() => setCount(count + 1)}>
        Click me
      </button>
    </div>
  );
}

export default Click;