Many people have the same question: How to get server response in model's failure function? It's easy to get response from server when operation success. But it's a little bit tricky to get response when operation fails. I saw a solution which add a listener to store's proxy to listen on exception event. But I found a easier way below.
model.save({ success: function (record, operation) { // json response from server console.log(operation.response); }, failure: function (record, operation) { // undefined console.log(operation.response); // json response from server console.log(operation.request.scope.reader.jsonData); } });