title: What is different between snapshot and prevState, prevProps from componentDidUpdate in react?
body: <p>I just started to studying React.</p>
  <p>When learning LifeCycle and I wonder about <code>componentDidUpdate</code> method.</p>
  <p>As I read <code>componentDidUpdate</code> method can have three params (<code>prevProps, prevState, snapshot</code>). If I can find out <code>prevState</code> from <code>componentDidUpdate</code> what is the <code>snapshot</code> for?</p>
  <p>It may not important but I just got curious</p>