[React]onclick 按鈕的寫法差異 – Different onClick this.fun vs this.fun()

<button onclick="myFunction()">Click me</button> <!-- 可以觸發 -->
<button onclick="myFunction">Click me</button> <!-- 不行 -->

<p id="demo"></p>

<script>
function myFunction() {
  document.getElementById("demo").innerHTML = "Hello World";
}
</script>

class App extends React.Component {
  handleClick = () => {
    console.log("test");
  };

  render() {
    return (
      <div>
        <button onClick={() => this.handleClick()}>Click me</button>
        <button onClick={this.handleClick}>Click me</button> {/*正常*/}
        <button onClick={this.handleClick()}>Click me</button> {/*會自動觸發一次*/}
      </div>
    );
  }
}