diff --git a/lib/util.js b/lib/util.js
index 2449f85e..75390bd1 100644
--- a/lib/util.js
+++ b/lib/util.js
@@ -107,7 +107,9 @@
             
             case 'array':
                 str         = ext.reduce(function(prev, cur) {
-                    var ret = prev += cur + '|';
+                    var ret;
+                    
+                    ret = prev + cur + '|';
                     
                     return ret;
                 }, '');