title: How should I handle a leave animation in componentWillUnmount in React?
body: <p>I was wondering if anyone could provide some insight about how they handle leave animations in React.js. I have been using Greensock TweenMax and the enter animations work fine on <code>componentDidMount</code>, but I haven't found a reliable way to animate a component out.</p>
  
  <p>My feeling is that it should go in <code>componentWillUnmount</code>, but React provides no callback mechanism for you to indicate when you are ready to let go of a component. Therefore the transition animation never completes since the animations are asynchronous to React. Instead, you see a tiny fraction of a second of animation, the component disappears, and is replaced by the next component animating in.</p>
  
  <p>This is a problem I have struggled with since I started using React 9 months ago. I can't help but think there has to be a solution out there other than <code>ReactCSSTransitionGroup</code> which I find to be cumbersome and finicky, especially with react-router.</p>