unmount components useeffect code example

Example 1: useeffect umnount

useEffect(() => {
    return () => {
      console.log("cleaned up");
    };
  }, []);

Example 2: componentdidupdate in hooks

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