const observer = useRef();...const lastMovieElementRef = useCallback( (node) => { if (observer.current) observer.current.disconnect(); observer.current = new IntersectionObserver((entries) => { if (entries[0].isIntersecting && hasMore) { setPage((prevPage) => prevPage + 1); } }); if (node) observer.current.observe(node); }, [hasMore]);동작 과정useCallback 설정: lastMovi..