Difference between attributes and toJSON methods in Backbone

Question

Is always equivalent use one or the other?

These prints in console same things

class Model extends Backbone.Model
  defaults:
    some: 'thing'
    other: 'item'

model = new Model

console.log model.attributes
console.log model.toJSON()

Answer 1

toJSON() is a standard method that the JavaScript JSON serializer looks for when serializing an object.

In the context of Backbone, if you override toJSON in your model you can change the format of values which get sent to the server when saving. For example you could filter out read only fields like time stamps.

attributes is the JavaScript object containing the model data, that's what gets altered when you use model.set(). Except if you don't use set() to alter values, then you bypass all the events and loose some of the benefits of backbone. So only use attributes directly if you know what you're doing.