当存在promise数据时显示子组件，并在子组件中呈现数据

import React, { useState, useEffect } from 'react';

const ParentComponent = () => {
  const [promiseData, setPromiseData] = useState(null);

  useEffect(() => {
    // 模拟异步操作，例如发送网络请求
    const fetchData = () => {
      return new Promise((resolve, reject) => {
        setTimeout(() => {
          resolve('这是异步数据');
        }, 2000);
      });
    };

    fetchData().then(data => {
      setPromiseData(data);
    });
  }, []);

  return (
    <div>
      {promiseData ? <ChildComponent data={promiseData} /> : null}
    </div>
  );
};

const ChildComponent = ({ data }) => {
  return <div>{data}</div>;
};

export default ParentComponent;