diff --git a/socks.js b/socks.js
index 2c33fdd..0306ea4 100755
--- a/socks.js
+++ b/socks.js
@@ -313,10 +313,12 @@ var proxyData = function () {
 };
 
 var defaults = function(obj) {
+    if (!obj) 
+        obj = {};
     Array.prototype.slice.call(arguments, 1).forEach(function(source) {
         if (source) {
             for (var prop in source) {
-                if (obj[prop] === null) {
+                if (typeof obj[prop] === 'undefined') {
                     obj[prop] = source[prop];
                 }
             }