Merge pull request #1240 from Violet-Bora-Lee/patch-23

Update article.md

1-js/04-object-basics/01-object/article.md

@@ -154,7 +154,7 @@ let user = {
 };
 
 let key = "name";
-user.key // undefined
+alert( user.key ) // undefined
 ```
 
 ### Computed properties