function DropdownNavbarItemDesktop()

in packages/docusaurus-theme-classic/src/theme/NavbarItem/DropdownNavbarItem.tsx [51:131]
77 lines of code
10 McCabe index (conditional complexity)

function DropdownNavbarItemDesktop({
  items,
  position,
  className,
  ...props
}: DesktopOrMobileNavBarItemProps) {
  const dropdownRef = useRef<HTMLDivElement>(null);
  const [showDropdown, setShowDropdown] = useState(false);

  useEffect(() => {
    const handleClickOutside = (event: MouseEvent | TouchEvent) => {
      if (
        !dropdownRef.current ||
        dropdownRef.current.contains(event.target as Node)
      ) {
        return;
      }
      setShowDropdown(false);
    };

    document.addEventListener('mousedown', handleClickOutside);
    document.addEventListener('touchstart', handleClickOutside);

    return () => {
      document.removeEventListener('mousedown', handleClickOutside);
      document.removeEventListener('touchstart', handleClickOutside);
    };
  }, [dropdownRef]);

  return (
    <div
      ref={dropdownRef}
      className={clsx('navbar__item', 'dropdown', 'dropdown--hoverable', {
        'dropdown--right': position === 'right',
        'dropdown--show': showDropdown,
      })}>
      <NavbarNavLink
        aria-haspopup="true"
        aria-expanded={showDropdown}
        role="button"
        href={props.to ? undefined : '#'}
        className={clsx('navbar__link', className)}
        {...props}
        onClick={props.to ? undefined : (e) => e.preventDefault()}
        onKeyDown={(e) => {
          if (e.key === 'Enter') {
            e.preventDefault();
            setShowDropdown(!showDropdown);
          }
        }}>
        {props.children ?? props.label}
      </NavbarNavLink>
      <ul className="dropdown__menu">
        {items.map((childItemProps, i) => (
          <NavbarItem
            isDropdownItem
            onKeyDown={(e) => {
              if (i === items.length - 1 && e.key === 'Tab') {
                e.preventDefault();
                setShowDropdown(false);
                const nextNavbarItem = dropdownRef.current!.nextElementSibling;
                if (nextNavbarItem) {
                  const targetItem =
                    nextNavbarItem instanceof HTMLAnchorElement
                      ? nextNavbarItem
                      : // Next item is another dropdown; focus on the inner
                        // anchor element instead so there's outline
                        nextNavbarItem.querySelector('a');
                  (targetItem as HTMLElement).focus();
                }
              }
            }}
            activeClassName={dropdownLinkActiveClass}
            {...childItemProps}
            key={i}
          />
        ))}
      </ul>
    </div>
  );
}