reactjs update state in useeffect code example

Example 1: useeffect on update

const isInitialMount = useRef(true);

useEffect(() => {
  if (isInitialMount.current) {
     isInitialMount.current = false;
  } else {
      // Your useEffect code here to be run on update
  }
});

Example 2: how to setstate in useeffect

React.useEffect(() => {
  let didCancel = false;
 
  // ...
  // you can check didCancel
  // before running any setState
  // ...
 
  return () => {
    didCancel = true;
  };
});