55 lines
1.3 KiB
TypeScript
55 lines
1.3 KiB
TypeScript
"use client";
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import { useEffect, useState } from "react";
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import { ChevronUp } from "lucide-react";
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import { Button } from "@/components/ui/button";
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import { cn } from "@/lib/utils";
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const SCROLL_THRESHOLD = 0.4; // show after 40% scroll
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export function ScrollToTop({ className }: { className?: string }) {
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const [visible, setVisible] = useState(false);
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useEffect(() => {
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function onScroll() {
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const maxScroll =
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document.documentElement.scrollHeight - window.innerHeight;
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if (maxScroll <= 0) {
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setVisible(false);
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return;
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}
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const ratio = window.scrollY / maxScroll;
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setVisible(ratio >= SCROLL_THRESHOLD);
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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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const scrollToTop = () => {
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window.scrollTo({ top: 0, behavior: "smooth" });
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};
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if (!visible) return null;
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return (
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<div
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className={cn(
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"fixed bottom-6 start-6 z-50 transition-opacity duration-300",
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className
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)}
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>
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<Button
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size="icon"
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variant="outline"
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onClick={scrollToTop}
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aria-label="برگشت به بالا"
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className="size-10 rounded-md shadow-md"
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>
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<ChevronUp className="size-5" />
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</Button>
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</div>
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);
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}
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