Tracks whether scrollerRef's element still has content below the fold.
A long option list clipped flush at a row boundary looks complete, and the scrollbar alone is a
weak signal — with a few hundred options the thumb is only a few pixels tall, and on platforms
with overlay scrollbars it reserves no width at all. Callers use this to draw an explicit cue.
The scroller must be attached by the time this hook's effect runs, and must stay mounted for the
hook's lifetime. The listeners bind to whatever scrollerRef.current holds then, and React does
not re-run an effect when a ref's contents change, so a scroller that mounts late or is swapped
for another element leaves the answer frozen at what the previous element reported. Mount the
hook alongside the scroller — as OptionListScrollCue does inside the popover's portal — rather
than above something that mounts it conditionally.
Parameters
scrollerRef: RefObject<null|HTMLElement>
Ref to the scrolling element.
isEnabled: boolean = true
Whether to observe at all. When false the hook reports false and attaches
nothing. Defaults to true.
Returns boolean
Whether the scroller currently has content below its visible area.
Tracks whether
scrollerRef's element still has content below the fold.A long option list clipped flush at a row boundary looks complete, and the scrollbar alone is a weak signal — with a few hundred options the thumb is only a few pixels tall, and on platforms with overlay scrollbars it reserves no width at all. Callers use this to draw an explicit cue.
The scroller must be attached by the time this hook's effect runs, and must stay mounted for the hook's lifetime. The listeners bind to whatever
scrollerRef.currentholds then, and React does not re-run an effect when a ref's contents change, so a scroller that mounts late or is swapped for another element leaves the answer frozen at what the previous element reported. Mount the hook alongside the scroller — asOptionListScrollCuedoes inside the popover's portal — rather than above something that mounts it conditionally.