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52efc7b | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 | /**
* @license
* Copyright 2025 Google LLC
* SPDX-License-Identifier: Apache-2.0
*/
import { useRef, useLayoutEffect, useCallback } from 'react';
/**
* A hook to manage batched scroll state updates.
* It allows multiple scroll operations within the same tick to accumulate
* by keeping track of a 'pending' state that resets after render.
*/
export function useBatchedScroll(currentScrollTop: number) {
const pendingScrollTopRef = useRef<number | null>(null);
// We use a ref for currentScrollTop to allow getScrollTop to be stable
// and not depend on the currentScrollTop value directly in its dependency array.
const currentScrollTopRef = useRef(currentScrollTop);
useLayoutEffect(() => {
currentScrollTopRef.current = currentScrollTop;
pendingScrollTopRef.current = null;
});
const getScrollTop = useCallback(
() => pendingScrollTopRef.current ?? currentScrollTopRef.current,
[],
);
const setPendingScrollTop = useCallback((newScrollTop: number) => {
pendingScrollTopRef.current = newScrollTop;
}, []);
return { getScrollTop, setPendingScrollTop };
}
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