code: function form (request) {
  
      if (isFormData(request.body)) {
          request.headers.delete('Content-Type');
      } else if (isObject(request.body) && request.emulateJSON) {
          request.body = Url.params(request.body);
          request.headers.set('Content-Type', 'application/x-www-form-urlencoded');
      }
  
  }
docs: Form data Interceptor.