react ref current parent rectangle code example

Example: how to get parent's ref react

constructor(props) {
    super(props);
    this.domElem = React.createRef();
}

getElem = () => {
    return this.domElem;
}

render() {
    return (
       <div>
           <div id="elem" ref={this.domElem}>Test Elem</div>
           <Child getParentElem={this.getElem}/>
       </div>
    )
}