React Scroll 감지

스크롤 이벤트 console 감지

  const [top, setTop] = useState(0);
  
  const handleScroll = () => {
    if (top > 299) {
      setTop(window.pageYOffset);
    } else {
      setTop(window.pageYOffset);
    }
    console.log(top);
  };

  useEffect(() => {
    const scrollListener = () => {
      window.addEventListener("scroll", handleScroll);
    };
    scrollListener();
    return () => {
      window.removeEventListener("scroll", handleScroll);
    };
  });