fix: handle CORS and URL slashes

- Added middleware to manage CORS headers for allowed origins
- Implemented automatic redirect to ensure URLs have trailing slashes

Co-Authored-By: Jagad Brahma Wiraatmaja <officialelsa21@gmail.com>

Author: sayaptawon

middleware.js

@@ -1,14 +1,19 @@
 import { NextResponse } from 'next/server';
 
-const allowedOrigins = ['https://sayaptawon.github.io', 'https://sayaptawon.vercel.app'];
+const allowedOrigins = [
+  'https://sayaptawon.github.io',
+  'https://sayaptawon.vercel.app',
+];
 
 const corsOptions = {
   'Access-Control-Allow-Methods': 'GET, POST, PUT, DELETE, PATCH, OPTIONS',
-  'Access-Control-Allow-Headers': 'Content-Type, Authorization, X-Requested-With',
+  'Access-Control-Allow-Headers':
+    'Content-Type, Authorization, X-Requested-With',
   'Access-Control-Allow-Credentials': 'true',
 };
 
-export function middleware(request) {
+export function middleware (request) {
+  const { pathname } = request.nextUrl;
   const origin = request.headers.get('origin') ?? '';
   const isAllowedOrigin = allowedOrigins.includes(origin);
   const isPreflight = request.method === 'OPTIONS';
@@ -21,6 +26,11 @@ export function middleware(request) {
     return NextResponse.json({}, { headers: preflightHeaders });
   }
 
+  if (!pathname.endsWith('/') && !pathname.includes('.')) {
+    const newUrl = `${request.nextUrl.origin}${pathname}/`;
+    return NextResponse.redirect(newUrl);
+  }
+
   const response = NextResponse.next();
 
   if (isAllowedOrigin) {
@@ -36,8 +46,5 @@ export function middleware(request) {
 }
 
 export const config = {
-  matcher: [
-    '/api/:path*',
-    '/((?!api|_next/static|_next/image|favicon.ico).*)',
-  ],
+  matcher: ['/api/:path*', '/((?!api|_next/static|_next/image|favicon.ico).*)'],
 };