如何在react中保存以前的组件DOM

class MyComponent extends React.Component {
  constructor(props) {
    super(props);
    this.myRef = React.createRef();
  }

  componentDidMount() {
    // 访问保存的组件DOM
    console.log(this.myRef.current);
  }

  render() {
    return <div ref={this.myRef}>保存的组件DOM</div>;
  }
}

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

  componentDidMount() {
    // 保存组件DOM
    this.setState({ previousDOM: this.renderPreviousDOM() });
  }

  renderPreviousDOM() {
    // 返回以前的组件DOM
    return <div>以前的组件DOM</div>;
  }

  render() {
    return (
      <div>
        {this.state.previousDOM}
        <div>当前的组件DOM</div>
      </div>
    );
  }
}