Calculate sub total emberjs - ember.js

Question

I create a shop cart. I using fixture adapter.
My models
App.Clothing = DS.Model.extend({
name: DS.attr('string')
, category: DS.attr('string')
, img: DS.attr('string')
, price: DS.attr('number')
, num: DS.attr('number')
, fullPrice: function(){
return this.get('price') + " $";
}.property('price')
})
App.CartRecord = App.Clothing.extend({
numInCart:DS.attr('number',{defaultValue:1})
, fullPrice: function(){
return this.get('price')*this.get('numInCart');
}.property('numInCart','price')
})
App.CartRecord.FIXTURES = [];
Route
App.CartRoute = Em.Route.extend({
model: function(){
return this.store.find('cartRecord');
}
})
And my controller
App.CartController = Em.ArrayController.extend({
totalPrice: 0
});
How i can calculate a total price?

Answer 1

You can put together a reduceComputed property for sum. Here are a few links for inspiration: one, two, and three. Basically, you can do something like this:
Ember.computed.sum = function (dependentKey) {
return Ember.reduceComputed.call(null, dependentKey, {
initialValue: 0,
addedItem: function (accumulatedValue, item, changeMeta, instanceMeta) {
return accumulatedValue + item;
},
removedItem: function (accumulatedValue, item, changeMeta, instanceMeta) {
return accumulatedValue - item;
}
});
};
Then, in your controller do something like this:
App.CartController = Em.ArrayController.extend({
prices: Ember.computed.mapBy('content', 'fullPrice'),
totalPrice: Ember.computed.sum('prices')
});