Scroll Trigger Utils

1function isWindowScroller(scroller: Element | Window): boolean {
2  return (
3    scroller === window ||
4    scroller === document.documentElement ||
5    scroller === document.body
6  );
7}
8 
9function waitForNextFrame(): Promise<void> {
10  return new Promise((resolve) => {
11    requestAnimationFrame(() => {
12      requestAnimationFrame(() => {
13        resolve();
14      });
15    });
16  });
17}
18 
19async function waitForScrollerReady(
20  scroller: Element | Window,
21  scrollReadyEvent?: string
22): Promise<void> {
23  await waitForNextFrame();
24 
25  if (!scrollReadyEvent || isWindowScroller(scroller)) {
26    if (!isWindowScroller(scroller)) {
27      await waitForNextFrame();
28    }
29    return;
30  }
31 
32  await Promise.race([
33    new Promise<void>((resolve) => {
34      window.addEventListener(scrollReadyEvent, () => resolve(), {
35        once: true,
36      });
37    }),
38    new Promise<void>((resolve) => {
39      window.setTimeout(resolve, 300);
40    }),
41  ]);
42 
43  await waitForNextFrame();
44}
45 
46function observeWindowResize(onResize: () => void): () => void {
47  let frameId = 0;
48 
49  const handleResize = () => {
50    cancelAnimationFrame(frameId);
51    frameId = requestAnimationFrame(onResize);
52  };
53 
54  window.addEventListener("resize", handleResize);
55 
56  return () => {
57    cancelAnimationFrame(frameId);
58    window.removeEventListener("resize", handleResize);
59  };
60}
61 
62export {
63  isWindowScroller,
64  observeWindowResize,
65  waitForNextFrame,
66  waitForScrollerReady,
67};