Possible to have sub Collections in Collection? - backbone.js

Question

I am learning Backbone.js and try to develop revamp a project using Backbong.js. As the project was already have APIs and was using in different platforms, iphone app, andorid app and web.
My problem is, there is a API return as below
{
success: true,
response: {
posts: [{...post data...}, {...post data...}, {...post data...}],
users: [{...user data...}, {...user data...}],
categories: [{...category data...}, {...category data...}]
}
}
as the backbone documentation
a Collection can contain many models
Typically the design is
// Post Model
var PostModel = Backbone.Model.extend({
...
})
// User Model
var UserModel = Backbone.Model.extend({
...
})
// Category Model
var UserModel = Backbone.Model.extend({
...
})
var PostListCollection = Backbone.Collection.extend({
model: PostModel
})
So... How can I put these 3 types of "objects" in the a Collection? Thanks

Answer 1

Unsure why you'd want a collection that isn't a single collection. It sounds like (and do correct me if this is wrong), you want a neat way of fetching your data from the API and turning it in to your three collections.
You could create a model that fetches from your API, that implements a custom parse function to create three collections within it.
Granted, you'll want to define UserCollection, PostCollection and CategoryCollection beforehand.
ApplicationModel = Backbone.Model.extend({
url: '/apiUrl/',
parse: function(data)
{
var result = {};
result.users = new UserCollection(data.users);
result.posts= new PostCollection(data.posts);
result.categories = new CategoryCollection(data.categories);
return result;
}
});

Answer 2

you can have a model that contain the collections
var ResultModel = Backbone.Model.extend({
default: {
Users: [],
Posts: [],
Categories: []
}
});
Then implements the collection in usual way.
So, when you try to get the child collections ...
var result = new ResultModel("your result JSON object");
var users = new UserCollection(result.get("Users"));
var posts = new PostCollection(result.get("Posts"));
var categories = new CategoryCollection(result.get("Category"));
This is working well for me ... in my case