shouldFloatFooter function - lastMutation

FloatingFooterWithReact-3d.tsx

const [mutationObserver, setMutationObserver] = 
	useState<MutationObserver>(null);

useEffect(() => {
  let delayedMutationEffect;

  function handleMutations(mutations: MutationRecord[]) {
    setLastMutation(mutations[mutations.length - 1]);
    delayedMutationEffect = setTimeout(() => setLastMutation(null), maxAnimationLength);
  }

  if (window.MutationObserver && !mutationObserver) {
    setMutationObserver(new MutationObserver(handleMutations));
  }

  return () => {
    if (mutationObserver) {
      mutationObserver.disconnect();
    }

    if (delayedMutationEffect) {
      clearTimeout(delayedMutationEffect);
    }
  };
}, [setMutationObserver, mutationObserver, maxAnimationLength]);