37 lines
1.4 KiB
TypeScript
37 lines
1.4 KiB
TypeScript
const isVerticalScrollContainer = (element: HTMLElement) => {
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if (element.scrollHeight <= element.clientHeight) return false;
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const overflowY = getComputedStyle(element).overflowY;
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return overflowY === "auto" || overflowY === "scroll";
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};
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const canScrollVertically = (element: HTMLElement, delta: number) => {
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return delta < 0 ? element.scrollTop > 0 : element.scrollTop + element.clientHeight < element.scrollHeight;
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};
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export const redirectShiftWheel = (root: HTMLElement, target: EventTarget | null, delta: number) => {
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if (delta === 0) return false;
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let current = target instanceof HTMLElement ? target : null;
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let startedInScrollContainer = false;
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while (current && root.contains(current)) {
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const isCurrentScrollContainer = isVerticalScrollContainer(current);
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startedInScrollContainer ||= isCurrentScrollContainer;
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if (isCurrentScrollContainer && canScrollVertically(current, delta)) {
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current.scrollTop += delta;
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return true;
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}
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if (current === root) break;
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current = current.parentElement;
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}
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if (startedInScrollContainer) return false;
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const viewport = [...root.querySelectorAll<HTMLElement>("[data-scrollbars='y'], [data-scrollbars='xy']")].find(
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(element) => isVerticalScrollContainer(element) && canScrollVertically(element, delta),
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);
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if (!viewport) return false;
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viewport.scrollTop += delta;
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return true;
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};
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