Hack to ensure error structures don't cause crash

In json.ErrorResponse object, the structure of the object is different based on the type of error Authorize.Net throws. It's not a good practice to assume the structure will always be the exact same. This is a temporary quick fix and not a permanent solution.

Author: richardgirges

Diff for: lib/AuthorizeNetGateway.js

@@ -80,7 +80,20 @@ function createJsonCallback (cb) {
         var json = result;
 
         if (json.ErrorResponse) {
-          throw new GatewayError(json.ErrorResponse[0].messages[0].message[0].text[0], json.ErrorResponse[0]);
+          if (
+            json.ErrorResponse[0] && 
+            json.ErrorResponse[0].messages && 
+            json.ErrorResponse[0].messages[0] && 
+            json.ErrorResponse[0].messages[0].message &&
+            json.ErrorResponse[0].messages[0].message[0] &&
+            json.ErrorResponse[0].messages[0].message[0].text &&
+            json.ErrorResponse[0].messages[0].message[0].text[0]
+          ) {
+            throw new GatewayError(json.ErrorResponse[0].messages[0].message[0].text[0], json.ErrorResponse[0]);
+          }
+          else {
+            throw new GatewayError(JSON.stringify(json.ErrorResponse));
+          }
         }
 
         return cb(json);