在功能组件中解决“对象作为React子级无效(found：[object Promise])”

const childElement = React.createElement('div', { key: 'child' }, 'Child Component');
const parentElement = React.createElement(ParentComponent, null, childElement);

class ParentComponent extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      data: null,
      isLoading: true
    };
  }

  componentDidMount() {
    fetchData().then(data => {
      this.setState({ data, isLoading: false });
    });
  }

  render() {
    const { data, isLoading } = this.state;

    if (isLoading) {
      return <div>Loading...</div>;
    }

    return <ChildComponent data={data} />;
  }
}

class ParentComponent extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      data: null
    };
  }

  componentDidMount() {
    fetchData().then(data => {
      this.setState({ data });
    });
  }

  componentDidUpdate() {
    const { data } = this.state;

    if (data) {
      this.renderChildComponent();
    }
  }

  renderChildComponent() {
    const { data } = this.state;
    return <ChildComponent data={data} />;
  }

  render() {
    return null;
  }
}