refactor: use cookie package for parsing and serializing auth cookies

src/lib/auth.js

@@ -1,26 +1,14 @@
 "use strict";
 
+const cookie = require("cookie");
+
 const COOKIE_NAME = "xartaudio_user";
 
 function parseCookies(cookieHeader) {
-  if (!cookieHeader) {
+  if (!cookieHeader || typeof cookieHeader !== "string") {
     return {};
   }
-
-  return String(cookieHeader)
-    .split(";")
-    .map((part) => part.trim())
-    .filter(Boolean)
-    .reduce((acc, pair) => {
-      const eq = pair.indexOf("=");
-      if (eq <= 0) {
-        return acc;
-      }
-      const key = pair.slice(0, eq).trim();
-      const value = pair.slice(eq + 1).trim();
-      acc[key] = decodeURIComponent(value);
-      return acc;
-    }, {});
+  return cookie.parse(cookieHeader);
 }
 
 function serializeUserCookie(userId, maxAgeSeconds) {
@@ -28,16 +16,25 @@ function serializeUserCookie(userId, maxAgeSeconds) {
     throw new Error("user_id_required");
   }
 
-  const encoded = encodeURIComponent(String(userId));
   const maxAge = Number.isInteger(maxAgeSeconds) && maxAgeSeconds > 0
     ? maxAgeSeconds
     : 60 * 60 * 24 * 30;
 
-  return `${COOKIE_NAME}=${encoded}; Path=/; HttpOnly; SameSite=Lax; Max-Age=${maxAge}`;
+  return cookie.serialize(COOKIE_NAME, String(userId), {
+    path: "/",
+    httpOnly: true,
+    sameSite: "lax",
+    maxAge,
+  });
 }
 
 function clearUserCookie() {
-  return `${COOKIE_NAME}=; Path=/; HttpOnly; SameSite=Lax; Max-Age=0`;
+  return cookie.serialize(COOKIE_NAME, "", {
+    path: "/",
+    httpOnly: true,
+    sameSite: "lax",
+    maxAge: 0,
+  });
 }
 
 function getAuthenticatedUserId(headers) {