title: AnchorEl for Popper in functional component
body: <p>How can i use <code>AnchorEl</code> for popover in functional component where <strong>this</strong> is not available. In component that extends <code>React.Component</code> i could use <code>buttonRef={node =&gt; { this.anchorEl = node;}}</code> on button and then in popper just set <code>anchorEl={this.anchorEl}</code>. But now I wanted to switch my Component to use Hooks and have this problem with <code>AnchorEl</code>. Can you help?</p>