Fixing possible bug in initialization of value

src/ngResource/resource.js

@@ -457,7 +457,7 @@ angular.module('ngResource', ['ng']).
               "Expected up to 4 arguments [params, data, success, error], got {0} arguments", arguments.length);
           }
 
-          var isInstanceCall = data instanceof Resource;
+          var isInstanceCall = this instanceof Resource;
           var value = isInstanceCall ? data : (action.isArray ? [] : new Resource(data));
           var httpConfig = {};
           var responseInterceptor = action.interceptor && action.interceptor.response || defaultResponseInterceptor;