40 lines
1.2 KiB
TypeScript
40 lines
1.2 KiB
TypeScript
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import React, { RefObject, useCallback, useState } from 'react';
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import { Box, as } from 'folds';
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import classNames from 'classnames';
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import * as css from './style.css';
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import {
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getIntersectionObserverEntry,
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useIntersectionObserver,
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} from '../../hooks/useIntersectionObserver';
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export const ScrollTopContainer = as<
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'div',
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{
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scrollRef?: RefObject<HTMLElement>;
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anchorRef: RefObject<HTMLElement>;
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onVisibilityChange?: (onTop: boolean) => void;
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}
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>(({ className, scrollRef, anchorRef, onVisibilityChange, ...props }, ref) => {
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const [onTop, setOnTop] = useState(true);
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useIntersectionObserver(
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useCallback(
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(intersectionEntries) => {
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if (!anchorRef.current) return;
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const entry = getIntersectionObserverEntry(anchorRef.current, intersectionEntries);
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if (entry) {
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setOnTop(entry.isIntersecting);
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onVisibilityChange?.(entry.isIntersecting);
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}
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},
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[anchorRef, onVisibilityChange]
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),
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useCallback(() => ({ root: scrollRef?.current }), [scrollRef]),
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useCallback(() => anchorRef.current, [anchorRef])
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);
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if (onTop) return null;
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return <Box className={classNames(css.ScrollTopContainer, className)} {...props} ref={ref} />;
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});
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