Question

I have a pretty simple collection, but I can’t seem to bind to it’s change event. In Chrome’s console, I’m running:

var c = new AwesomeCollection();
c.bind("change", function(){
  console.log('Collection has changed.');
});

c.add({testModel: "Test"}); // Shouldn't this trigger the above log statement?

Since this is one of those things that can be difficult to track down, I doubt anybody knows off the top of their head what’s going on (if so, great!). So, I’m asking two questions:

1. Should the above code work as anticipated?
2. If so, do you have any suggestions on how to track down where this would fail?

Thanks

Answer 1

The change event is only fired when one of the collections’ models are modified. When a model is added to the collection the add event is fired.
See Backbone.js’ Collection Documentation:

You can to bind “change” events to be notified when any model in the
collection has been modified, listen for “add” and “remove”
events[…]

To listen for when an add occurs modify your code to be

var c = new AwesomeCollection();
c.bind("add", function(){
  console.log('Collection has changed.');
});

c.add({testModel: "Test"});