38 lines
858 B
TypeScript
38 lines
858 B
TypeScript
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/**
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* ScrollToTop — fixed ↑ button that appears after scrolling down.
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* Smooth-scrolls back to the top when clicked.
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*/
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'use client';
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import { useState, useEffect } from 'react';
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const SHOW_THRESHOLD = 300;
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export function ScrollToTop() {
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const [visible, setVisible] = useState(false);
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useEffect(() => {
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const onScroll = () => {
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setVisible(window.scrollY > SHOW_THRESHOLD);
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};
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window.addEventListener('scroll', onScroll, { passive: true });
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return () => window.removeEventListener('scroll', onScroll);
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}, []);
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const scrollToTop = () => {
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window.scrollTo({ top: 0, behavior: 'smooth' });
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};
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return (
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<button
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className={`scroll-to-top ${visible ? 'scroll-to-top--visible' : ''}`}
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onClick={scrollToTop}
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aria-label="Scroll to top"
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type="button"
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>
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↑
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</button>
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);
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}
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