Represent an array of a model in Ember

I am writing a Music player Component with favorites songs from SoundCloud using their API

I want automatically play the next favorite song once the previous is finished.

The idea is to create a new property to represent an array of all my favorites to pass the nextFavorite

This is my player controller

sortedFavorites: Ember.computed.alias('favorites’),

and

actions: {
    selectFavorite: function(favorite, index, play) {
            if (!this.get('externalPlay')) {
                index = index + 1;
                nextFavorite = this.get('sortedFavorites').nextObject(index, favorite);
                self.set('nextFavorite', nextFavorite);
            }
            return SC.stream(favoritePath, {
                onfinish: function() {
                    self.set('isPlaying', false);
                    if (self.get('nextFavorite') != null) {
                        return self.send('selectFavorite', self.get('nextFavorite'), index);
                    }
                }
            }
        }
   }
}

When i create a new property the alias for “favorites” , it is undefined

In case i create an alias for a single favorite i can access to my single favorite although it’s not what i need to do

so how can the sortedFavorites be an array of all my favorites in order to access to the nextObject (favorite)?