How do I replace a model in a Backbone.Collection?

Question

Suppose I have a Backbone.Collection with three models. I want to replace the middle one, keeping the first and third models in their current positions. (Assume there's no comparator.) How do I do this?

Answer 1

This is a good question and still relevant today, so it's worth answering.

It is possible the functionality used in my answer did not exist when you asked the question, but it is now quite straightforward to do this.

Anyway, lets assume your collection is named myCollection and already has 3 models stored in it. Lets also say you have a new model named newModel that you want use to replace the existing middle model in the collection. To replace the middle model, leaving the first and third models untouched, you can do this:

myCollection.remove(myCollection.at(1));

myCollection.add(newModel, {at: 1});

This will do exactly what you want and raise the remove event for the model removed and the add event for the replacement, which is what you wanted also.

Answer 2

There is a simple mechanism built into Backbone that handles this issue

myCollection.add(newModel, {merge: true});