hello-hook.html

web-cheat/react/hello-hook.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)
  const handleClick = React.useCallback(() => {
    console.log('handleClick');
    setN(n => n + 1)
  }, [setN])
  return (
    <div>
      <div onClick={handleClick}>Click me</div>
      <div>{n}</div>
      <div>{Math.floor(n / 2)}</div>
    </div>
  )
}

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