Caching and walking an ArrayController

Question

I have a Phone model. I want to cache all phones on my application:

cachePhones : function () {
    this.set('phones', this.Phone.find());
},

And get the countries for which I have available phones:

getCountries : function () {
    var phones = this.get('phones.content');
    var countries = new this.dataSet(), country;
    console.log('phones=%o', phones.length);
    for (var index = 0, length = phones.length; index < length; index++) {
        country = phones[index].record.get('country');
        console.log('Adding %o', country);
        countries.add(country, true);
    }
    console.log('countries=%o', countries.keys());
    return countries.keys();
},

(dataSet is just a set implementation in javascript)

I am not sure this is the right way to walk the ArrayController:

do I really need to access the content?
do I really need to access record?

This feels like hacking around my way in the ember internals. I have tried before this:

var phones = this.get('phones');
var countries = new this.dataSet(), country;
for (var index = 0, length = phones.length; index < length; index++) {
    country = phones[index].country;
    countries.add(country, true);
}

But it was not working at all. What is the canonical way of walking an ArrayController?

You can use Ember.Set.create(); instead of new this.dataSet();. Ember have your own Set implementation ;) — Marcio Junior, Aug 06 '13 at 14:25

score 2 · Accepted Answer · answered Aug 06 '13 at 14:19

2

Have you tried something like this? Normally you should always be fine with using the functional methods Ember offers for its collections.

var phones = this.get('phones');
var countries = new this.dataSet(), country;
phones.forEach(function(phone, index){
  country = phone.get("country");
  countries.add(country, true);
});

answered Aug 06 '13 at 14:19

mavilein

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Looks much cleaner than my implementation. I'll try that, thanks. – blueFast Aug 06 '13 at 14:28

score 2 · Answer 2 · answered Aug 06 '13 at 14:25

2

Besides @mavilein correct answer one thing worth mentioning is that if you have a model like App.Phone then after you do App.Phone.find() and the records are fetched, your Store has already a cache which you can consult with App.Phone.all() this will not make another request but gives you the records available in the Store.

Hope it helps.

answered Aug 06 '13 at 14:25

intuitivepixel

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What if I do not know if the phones have already been requested? Can I access `App.Phone.all()`, and a `App.Phone.find()` will be done automatically? – blueFast Aug 06 '13 at 15:22
no, `.all()` only retrieves the already fetched records if any, see here: https://github.com/emberjs/data/blob/master/packages/ember-data/lib/system/store.js#L848 – intuitivepixel Aug 06 '13 at 16:12

Caching and walking an ArrayController

2 Answers2