fix: preserve scroll position on navbar back button

Updates navbar back navigation to maintain scroll position when returning
to previous page. Prevents unwanted scroll reset and improves UX.

Add scroll position tracking
Modify back button handler
Implement position restoration

src/components/Navbar.tsx

@@ -2,8 +2,8 @@
 
 import { motion, AnimatePresence } from 'framer-motion';
 import { useSession } from 'next-auth/react';
-import { usePathname, useRouter } from 'next/navigation';
-import React, { useState, useCallback, useMemo } from 'react';
+import { usePathname } from 'next/navigation';
+import React, { useState, useCallback, useMemo, useEffect } from 'react';
 import Link from 'next/link';
 import { ArrowLeft, Menu, Search, X } from 'lucide-react';
 import { Button } from './ui/button';
@@ -12,9 +12,13 @@ import ThemeToggler from './ThemeToggler';
 import ProfileDropdown from './profile-menu/ProfileDropdown';
 import { SearchBar } from './search/SearchBar';
 
+//global map data structure to store scroll position
+
+const scrollPositions = new Map<string, number>();
+
 export const Navbar = () => {
   const { data: session } = useSession();
-  const router = useRouter();
+
   const [isMenuOpen, setIsMenuOpen] = useState(false);
   const [isSearchOpen, setIsSearchOpen] = useState(false);
   const pathname = usePathname();
@@ -40,6 +44,33 @@ export const Navbar = () => {
     [],
   );
 
+  // Save scroll position when leaving a page
+  useEffect(() => {
+    const handleScroll = () => {
+      scrollPositions.set(pathname, window.scrollY);
+    };
+
+    window.addEventListener('scroll', handleScroll);
+
+    return () => window.removeEventListener('scroll', handleScroll);
+  }, [pathname]);
+
+  // Custom back navigation with scroll position restoration
+
+  const handleBack = useCallback(() => {
+    scrollPositions.set(pathname, window.scrollY);
+
+    // Use window.history to go back
+    window.history.back();
+
+    // Restore scroll position after a short delay to ensure the page has loaded
+    setTimeout(() => {
+      const previousPath = window.location.pathname;
+      const savedPosition = scrollPositions.get(previousPath) || 0;
+      window.scrollTo(0, savedPosition);
+    }, 100);
+  }, [pathname]);
+
   return (
     <>
       <motion.nav
@@ -63,7 +94,7 @@ export const Navbar = () => {
           >
             {session?.user && pathname !== '/home' && (
               <Button
-                onClick={() => router.back()}
+                onClick={handleBack}
                 variant={'ghost'}
                 size={'icon'}
                 className="flex items-center gap-2"
@@ -158,9 +189,9 @@ export const Navbar = () => {
                 exit={{ opacity: 0, y: -20 }}
               >
                 <AppbarAuth />
-                  <Button variant={'branding'} className="w-full">
+                <Button variant={'branding'} className="w-full">
                   <Link
-                      href={'https://harkirat.classx.co.in/new-courses'}
+                    href={'https://harkirat.classx.co.in/new-courses'}
                     target="_blank"
                   >
                     Join now