How to get the position of another element in ReactJS? : <p>My parent element has 2 child, the 2nd child can be dragged into the first child.</p>

<p>if it's dragged correctly (into the first child), a callback will be triggered.</p>

<p>how can I know if the drag ended in the correct location?</p>

<p>I'm using react-draggable.</p>
