hook for didupdate code example

Example 1: componentdidupdate in hooks

const App = props => {
  const didMountRef = useRef(false)
  useEffect(() => {
    if (didMountRef.current) {
      doStuff()
    } else didMountRef.current = true
  }
}

Example 2: react useeffect on change props

useEffect(() => console.log('value changed!'), [props.isOpen]);