38 lines
1.0 KiB
TypeScript
38 lines
1.0 KiB
TypeScript
'use client';
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import { useEffect, useState } from 'react';
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export function BackToTop() {
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const [visible, setVisible] = useState(false);
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useEffect(() => {
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const onScroll = () => {
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if (window.scrollY > 400) {
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setVisible(true);
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} else {
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setVisible(false);
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}
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};
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onScroll();
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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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if (!visible) return null;
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return (
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<button
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type="button"
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onClick={() => {
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window.scrollTo({ top: 0, behavior: 'smooth' });
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}}
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aria-label="回到頁面頂部"
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className="fixed bottom-6 right-4 z-40 inline-flex h-9 w-9 items-center justify-center rounded-full bg-slate-900 text-slate-50 shadow-md ring-1 ring-slate-800/70 transition hover:bg-slate-700 dark:bg-slate-100 dark:text-slate-900 dark:ring-slate-300/70 dark:hover:bg-slate-300"
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>
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<span className="text-lg leading-none">↑</span>
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</button>
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);
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}
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