Function MenuPlacer

packages/react-select/src/components/Menu.tsx:312–374

(
  props: MenuPlacerProps<Option, IsMulti, Group>
)

// NOTE: internal only
export const MenuPlacer = <
  Option,
  IsMulti extends boolean,
  Group extends GroupBase<Option>
>(
  props: MenuPlacerProps<Option, IsMulti, Group>
) => {
  const {
    children,
    minMenuHeight,
    maxMenuHeight,
    menuPlacement,
    menuPosition,
    menuShouldScrollIntoView,
    theme,
  } = props;

  const { setPortalPlacement } = useContext(PortalPlacementContext) || {};
  const ref = useRef<HTMLDivElement | null>(null);
  const [maxHeight, setMaxHeight] = useState(maxMenuHeight);
  const [placement, setPlacement] = useState<CoercedMenuPlacement | null>(null);
  const { controlHeight } = theme.spacing;

  useLayoutEffect(() => {
    const menuEl = ref.current;
    if (!menuEl) return;

    // DO NOT scroll if position is fixed
    const isFixedPosition = menuPosition === 'fixed';
    const shouldScroll = menuShouldScrollIntoView && !isFixedPosition;

    const state = getMenuPlacement({
      maxHeight: maxMenuHeight,
      menuEl,
      minHeight: minMenuHeight,
      placement: menuPlacement,
      shouldScroll,
      isFixedPosition,
      controlHeight,
    });

    setMaxHeight(state.maxHeight);
    setPlacement(state.placement);
    setPortalPlacement?.(state.placement);
  }, [
    maxMenuHeight,
    menuPlacement,
    menuPosition,
    menuShouldScrollIntoView,
    minMenuHeight,
    setPortalPlacement,
    controlHeight,
  ]);

  return children({
    ref,
    placerProps: {
      ...props,