React Base Fiddle (JSX)

Starting point for creating JSFiddles with React.

by leopoldthecuber

HTML

<script src="https://unpkg.com/react@16/umd/react.development.js"></script>
<script src="https://unpkg.com/react-dom@16/umd/react-dom.development.js"></script>
<div id="container">
    <!-- This element's contents will be replaced with your component. -->
</div>

Babel + JSX

const Hello = () => {
  const ref = React.useRef(null);
  const [flag, setFlag] = React.useState(false);
  const a = () => {
    setFlag(true);
    console.log(!!ref.current);
    setTimeout(() => {
      console.log(!!ref.current);
    });
  }
  if (flag) {
  	return <input ref={ref} type="text"></input>;
  }
  
  return <div onClick={a}>Hello</div>;
}

ReactDOM.render(
  <Hello />,
  document.getElementById('container')
);