diff --git a/www/helpers.js b/www/helpers.js
index ecdb100..7e17616 100644
--- a/www/helpers.js
+++ b/www/helpers.js
@@ -293,22 +293,25 @@ module.exports = function init(global, jsUtil, cookieHandler, messages, base64,
       }
 
       try {
-        // json
-        if (responseType === validResponseTypes[1]) {
-          response.data = JSON.parse(response.data);
-        }
-
-        // arraybuffer
-        else if (responseType === validResponseTypes[2]) {
-          response.data = base64.toArrayBuffer(response.data);
-        }
-
-        // blob
-        else if (responseType === validResponseTypes[3]) {
-          var buffer = base64.toArrayBuffer(response.data);
-          var type = response.headers['content-type'] || '';
-          var blob = new Blob([ buffer ], { type: type });
-          response.data = blob;
+        // to allow empty responses: only post process data if it is set
+        if (response.data) {
+          // json
+          if (responseType === validResponseTypes[1]) {
+            response.data = JSON.parse(response.data);
+          }
+  
+          // arraybuffer
+          else if (responseType === validResponseTypes[2]) {
+            response.data = base64.toArrayBuffer(response.data);
+          }
+  
+          // blob
+          else if (responseType === validResponseTypes[3]) {
+            var buffer = base64.toArrayBuffer(response.data);
+            var type = response.headers['content-type'] || '';
+            var blob = new Blob([ buffer ], { type: type });
+            response.data = blob;
+          }
         }
 
         success(response);