diff --git a/6-data-storage/01-cookie/article.md b/6-data-storage/01-cookie/article.md
index e91a854e..ba1ffa71 100644
--- a/6-data-storage/01-cookie/article.md
+++ b/6-data-storage/01-cookie/article.md
@@ -310,7 +310,7 @@ function setCookie(name, value, options = {}) {
     ...options
   };
 
-  if (options.expires.toUTCString) {
+  if (options.expires && options.expires.toUTCString) {
     options.expires = options.expires.toUTCString();
   }