Ember Data grab already loaded objects from store

Using Ember 1.13.6 and Ember Data 1.13.7, I am wondering how I can get the already loaded objects from the store without doing a call to the server (where relationship is async).

Image following model:

//page model
export default DS.Model.extend({
    parent: DS.belongsTo('page', { async: false, inverse: 'subpages'}),
    subpages: DS.hasMany('page',{ async: true, inverse: 'parent' }),
 });

If you just call model.get('subpages'), Ember Data returns a promise + make a call to the server. Normally this is fine behaviour, but now I got a special case I just want to grab the already loaded objects.

I can't find anything about such case in the docs. The only way I found at the moment is by using private properties:

model._internalModel._relationships.initializedRelationships.subpages.canonicalState

Of course I seek a normal way to achieve this, without touching the inner code of Ember Data. So does anyone know how to achieve this?