useEffect cleanup funtion

Warning: Can't perform a React state update on an unmounted component.
This is a no-op, but it indicates a memory leak in your application.
To fix, cancel all subscriptions and asynchronous tasks in a useEffect
cleanup function.

  useEffect(() => {
    axios.post("/api/like/get-like-state", variable).then((res) => {
      if (res.data.success && res.data.liked) {
        setLiked(res.data.liked);
      }
    });
  }, [variable]);

useEffect(() => {
    let mounted = true;
    // 좋아요 상태 가져오기
    axios.post("/api/like/get-like-state", variable).then((res) => {
      if (res.data.success && res.data.liked && mounted) {
        setLiked(res.data.liked);
      }
    });

    // clean-up
    return () => (mounted = false);
  }, [variable]);

const Example = (props) => {
  const unmounted = useRef(false);
  useEffect(() => {
    return () => { unmounted.current = true }
  }, []);

  const setFilter = () => {
    // ...
    props.dispatch(fetchCourses()).then(() => {
      if (!unmounted.current) {
        setLoading(false);
      }
    })
  }

  // ...
  return (
    <ReactTable onFetchData={setFilter} /* other props omitted */ />
  );
}