For Loop over Backbone Collection

Fairly new to backbone, so this is a really basic question. I have a Backbone collection passed into a function and I can prove that it has been passed and that the models in the collection have ids.

Here's how I'm setting the ids -

convertToMapObjects: (results)  =>
   objectList = new ObjectList()
   results.each(result)->
    testObj = new TestObject()
    testObj.set
      id = result.get("id")
    objectList.add(testObj)

And in another function ( accessed through making the model trigger an event) -

getIds: (objects) =>
ids = (object.id for object in objects) 

I think the issue may be because of how I'm iterating through the collection because when I tried doing

for object in objects
   console.log(object)

I saw two undefineds. Is this correct? If so, why can't I use a for loop to go through a backbone collection? Also, is there a way I could do so?