小编Mah*_*ari的帖子

const App = (props) => {
  var [count, setCount] = React.useState(0);

  return (
    <span>{count}</span>
  );
};

ReactDOM.render(<App />, document.getElementById("root"));

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>
<div id="root"></div>