import { MutableRefObject, useEffect, useMemo, useState } from "react"; type RefType = MutableRefObject | Window; export function useResizeObserver(...refs: RefType[]) { const [dimensions, setDimensions] = useState< { width: number; height: number; x: number; y: number }[] >( new Array(refs.length).fill({ width: 0, height: 0, x: -Infinity, y: -Infinity, }), ); const resizeObserver = useMemo( () => new ResizeObserver((entries) => { window.requestAnimationFrame(() => { setDimensions(entries.map((entry) => entry.contentRect)); }); }), [], ); useEffect(() => { refs.forEach((ref) => { if (ref instanceof Window) { resizeObserver.observe(document.body); } else if (ref.current) { resizeObserver.observe(ref.current); } }); return () => { refs.forEach((ref) => { if (ref instanceof Window) { resizeObserver.unobserve(document.body); } else if (ref.current) { resizeObserver.unobserve(ref.current); } }); }; }, [refs, resizeObserver]); if (dimensions.length == refs.length) { return dimensions; } else { const items = [...dimensions]; for (let i = dimensions.length; i < refs.length; i++) { items.push({ width: 0, height: 0, x: -Infinity, y: -Infinity, }); } return items; } }