From 042073f1d679b9c7fb7d64660d3c6d372bd1f468 Mon Sep 17 00:00:00 2001
From: Douglas Christopher Wilson <doug@somethingdoug.com>
Date: Tue, 29 Mar 2022 17:25:05 -0400
Subject: [PATCH] Fix expires option to reject invalid dates

---
 HISTORY.md        |  1 +
 index.js          | 19 +++++++++++++++++--
 test/serialize.js |  4 ++++
 3 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/HISTORY.md b/HISTORY.md
index 985e359..f58a165 100644
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -2,6 +2,7 @@ unreleased
 ==========
 
   * Add `priority` option
+  * Fix `expires` option to reject invalid dates
 
 0.4.2 / 2022-02-02
 ==================
diff --git a/index.js b/index.js
index 57d545e..31f6c7d 100644
--- a/index.js
+++ b/index.js
@@ -20,6 +20,7 @@ exports.serialize = serialize;
  * @private
  */
 
+var __toString = Object.prototype.toString
 var decode = decodeURIComponent;
 var encode = encodeURIComponent;
 
@@ -145,11 +146,13 @@ function serialize(name, val, options) {
   }
 
   if (opt.expires) {
-    if (typeof opt.expires.toUTCString !== 'function') {
+    var expires = opt.expires
+
+    if (!isDate(expires) || isNaN(expires.valueOf())) {
       throw new TypeError('option expires is invalid');
     }
 
-    str += '; Expires=' + opt.expires.toUTCString();
+    str += '; Expires=' + expires.toUTCString()
   }
 
   if (opt.httpOnly) {
@@ -205,6 +208,18 @@ function serialize(name, val, options) {
   return str;
 }
 
+/**
+ * Determine if value is a Date.
+ *
+ * @param {*} val
+ * @private
+ */
+
+function isDate (val) {
+  return __toString.call(val) === '[object Date]' ||
+    val instanceof Date
+}
+
 /**
  * Try decoding a string using a decoding function.
  *
diff --git a/test/serialize.js b/test/serialize.js
index 57ac661..06c8207 100644
--- a/test/serialize.js
+++ b/test/serialize.js
@@ -67,6 +67,10 @@ test('expires', function() {
   assert.throws(cookie.serialize.bind(cookie, 'foo', 'bar', {
     expires: Date.now()
   }), /option expires is invalid/);
+
+  assert.throws(cookie.serialize.bind(cookie, 'foo', 'bar', {
+    expires: new Date(NaN)
+  }), /option expires is invalid/)
 });
 
 test('priority', function () {