A different way of handling this promise?

Here’s a little bit of CoffeeScript, but feel free to answer in JavaScript:

model = new MyModel content: content
model.save()
@collection.add model

Elsewhere, a view is listening for the add event on the collection:

_addOne: (model, collection, options)=>
  view = new MyView model: model
  @subviews[model.id] = view

Sometimes the model hadn’t finished talking to the server, so it didn’t have an id and this code failed to do what was wanted. So, I wrapped the save in a promise using the when.js library (when is mapped to When here)

When model.save()
  .then =>
    @collection.add model

Now all is hunky dory with the world. What I’m wondering is, is there a way to get the then into the _addOne method, because that’s the bit that’s really waiting, the collection itself doesn’t mind getting a half-baked model added to it.

How can I proceed?

Answer

Use Collection#create instead:

createcollection.create(attributes, [options])

Convenience to create a new instance of a model within a collection. Equivalent to instantiating a model with a hash of attributes, saving the model to the server, and adding the model to the set after being successfully created. […] Pass {wait: true} if you’d like to wait for the server before adding the new model to the collection.

So if you do this:

@collection.create(
  { content: content }
  { wait: true }
)

Then the model won’t be added to the collection until the server has responded and the model will have its server-supplied id by then.