The expires option can be either a number or a Date object. (https://github.com/carhartl/jquery-cookie#expires)

Since there is no option to define both for a property it should be defined as any.

jquery.cookie/jquery.cookie.d.ts

@@ -5,8 +5,9 @@
 
 ///<reference path="../jquery/jquery-1.8.d.ts" />
 
+
 interface JQueryCookieOptions {
-    expires?: number;
+    expires?: any;
     path?: string;
     domain?: string;
     secure?: bool;