Unable to get hasMany association - ember.js

Question

I used commit eaa1123 (ember) and 508479d (ember-data) to build the JS files.
I have the following JSON returned from my Rails backend, which is generated with active_model_serializers (0.6.0):
{
"posts": [
{
"id": 408,
"title": "Lorem Ipsum",
"body": "In at quo tempora provident nemo.",
"comments": [
{
"id": 956,
"body": "Quo incidunt eum dolorem."
},
...
]
}
]
}
and the following Ember models:
App.Post = DS.Model.extend({
title: DS.attr('string'),
body: DS.attr('string'),
comments: DS.hasMany('App.Comment', {
embedded: true
})
});
App.Comment = DS.Model.extend({
body: DS.attr('string'),
post: DS.belongsTo('App.Post')
});
All look perfectly normal:
post = App.Post.find(408);
post.get('title')
// => "Lorem Ipsum"
However, I can't seem to get to the comments:
comments = post.get('comments')
comments.get('firstObject') instanceof App.Comment
// => true
comments.forEach(function(comment) {
console.log(comment.get('body'))
})
//=> undefined
When I use:
comments.content
I get an Array that contain objects, so:
comments.content[0]
//=> { body: "Quo incidunt eum dolorem.", id: 956 }
but this is not what I expected.
It seems so obvious, so I must be doing something wrong.
As a side-effect: currently I'm not able to render my comments in a template in a easy way, so I hope someone can help me on this one.
Thanks in advance.

Answer 1

If you used that commit it means you are on the latest ember-data revision, which is 11. Adding embedded: true to load an embedded association was deprecated a while back between revision 5 or 9, not too sure again.
If you are using the default restAdapter, you now need to define embedded loading as a mapping as shown below and not as an association option:
App.store = DS.Store.create({
revision: 11,
adapter: DS.RESTAdapter.create()
});
App.store.adapter.serializer.map('App.Post', {
comments: {embedded: 'load'}
});
App.Post = DS.Model.extend({
title: DS.attr('string'),
body: DS.attr('string'),
comments: DS.hasMany('App.Comment')
});
App.Comment = DS.Model.extend({
body: DS.attr('string'),
post: DS.belongsTo('App.Post')
});
You can follow all the previous discussion on it through the links below:
https://github.com/emberjs/data/issues/504#issuecomment-11256934
https://github.com/emberjs/data/pull/430#issuecomment-10925506
Various fixes for loading embedded records:
https://github.com/emberjs/data/pull/541
This not directly related but incase all i wrote above fails, then add this solution to the mix
BelongsTo association are not materialized when using findAssociation and extractHasMany hooks for async HasMany:
https://github.com/emberjs/data/issues/525
The internals for anyone who wants to quickly see where things are defined with respect to the call to 'App.store.adapter.serializer.map'
When we called 'App.store.adapter.serializer.map', the call to serializer is defined on line 536 below and the map is online 696 in the 2nd link
https://github.com/emberjs/data/blob/master/packages/ember-data/lib/system/adapter.js#L536
https://github.com/emberjs/data/blob/master/packages/ember-data/lib/system/adapter.js#L696
On line 67 of the DS.RESTAdapter which extends DS.Adapter, the serializer property is made to point to DS.RESTSerializer where additional functionality specific to the RestAdapter are added.
https://github.com/emberjs/data/blob/master/packages/ember-data/lib/adapters/rest_adapter.js#L67