diff --git a/lib/index.js b/lib/index.js
index 05f6f45..6a90e8a 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -76,6 +76,8 @@ var strftime = (function() {
             }
         });
     }
+    return strftime;
 }());
 
 if (typeof exports !== 'undefined') exports.strftime = strftime;
+else (function(global) { global.strftime = strftime }.call(this));