Question

Using backbone.js – I want to bind an event to any change in the model and the collections/models that are nested inside it.

Right now I do an @bind 'change', () -> when initializing the base model.

How can I pass data on any change, even that of deep nested models? Does the change event carry variables with it? I need things like the model’s collection, id, attributes, etc.

Thanks.

Answer 1

Does the change event carry variables with it?

Yes, the change event gets two arguments: First, the model itself; second, the new attribute value. There are several methods available on the model that are aimed specifically at getting information during a change event. See the docs on hasChanged, changedAttributes, previous, and previousAttributes.

So for instance, to access the previous attributes of a model each time it changes, you’d write

@bind 'change', (model) ->
  prevAttrs = model.previousAttributes()
  ...