diff --git a/src/form2js.js b/src/form2js.js
index 8814f46..e9c2d9d 100644
--- a/src/form2js.js
+++ b/src/form2js.js
@@ -253,6 +253,11 @@
 
         callbackResult = nodeCallback && nodeCallback(node);
 
+        //if the callback returns undefined do not serialize the node
+        if (nodeCallback && typeof(callbackResult) === 'undefined') {
+            return [];
+        }
+
         if (callbackResult && callbackResult.name) {
             result = [callbackResult];
         }