Backbone.js partial model update

Question

Is it possible to send just the modified properties of a model when saving the changes?

BTW, Are there any "official" Backbone.js group/mailing list to ask this kind of questions?

Answer 1

Backbone does not support this out of the box, but you have all the tools to make that happen. If you look at Backbone.sync you will see that it calls toJSON on your model to get the actual data to send. Now you might have to tweak this out, but here is the gist of it:

initialize: function(){   this.dirtyAttributes = {} }, set: function(attrs, options){   Backbone.Model.prototype.set.call(this, attrs, options);   _.extend(this.dirtyAttributes, attrs); }, toJSON : function(){   json = this.dirtyAttributes;   this.dirtyAttributes = {};   return json; } 

If you want a complete solution you need to apply the same logic to unset, clear, save, etc. But I guess you get how to do this. I put the reset of the dirty attributes in the toJSON function, but it should really be in the success callback (when calling save).

Answer 2

Currently backbone does not support sending part of the model to the server. It would be an interesting addition though.

If you browse the source you can see that Backbone.sync (the part of backbone that is responsible for communicating with the data store) is one of the simplest components in backbone and simply wraps the ajax support in jQuery or Zepto.

UPDATE

starting backbone version 0.9.10, partial model update is supported natively via

model.save(attrs, {patch: true})