Function callback

packages/shared/src/components/ScrollToTopButton.tsx:30–37

()

  useEffect(() => {
    const callback = () => {
      const shouldShow =
        document.documentElement.scrollTop >= window.innerHeight / 2;
      setShow(shouldShow);
      if (shouldShow) {
        setHasShown(true);
      }
    };
    callback();
    window.addEventListener('scroll', callback, { passive: true });
    return () => window.removeEventListener('scroll', callback);