react/hello-hook-use-effect.html

react/hello-hook-use-effect.html
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<script src="https://unpkg.com/react@17/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@17/umd/react-dom.development.js"></script>
<script src="https://unpkg.com/@babel/standalone@7.14.7/babel.min.js"></script>
</head>
<body>
<p><a href="https://cirosantilli.com/react">https://cirosantilli.com/react</a></p>
<div id="root"></div>
<script type="text/babel">
function Main(props) {
  console.log('Main');
  const [n, setN] = React.useState(0)
  React.useEffect(() => {
    console.error('useEffect')
  })
  React.useEffect(() => {
    console.error('useEffect2')
  })
  function handleClick() {
    console.log('handleClick');
    setN(n => n + 1)
  }
  return (
    <div>
      <div onClick={handleClick}>Click me</div>
      <div>{n}</div>
    </div>
  )
}

ReactDOM.render(
  <Main />,
  document.getElementById('root')
);
</script>
</body>
</html>