title: Pass React Ref from parent to child in order to get DOM element
body: <p>I have a parent and a child component. I need to access the parent's <code>HTMLelement</code> in the child component.</p>
  
  <p>I have a working but unclean solution involving
  <code>this.setState({ domNode: ReactDOM.findDOMNode(this) });</code> in the parent's <code>componentDidMount</code> which is just wrong on many levels.</p>
  
  <p>How can i do this using <code>createRef()</code> in the parent to pass its ref as a prop to the child and then how do i get the DOM node with type <code>HTMLElement</code> from the ref?</p>