How to represent arrays within ember-data models?

Well... It was a little bit difficult but mixing all answers in this post I made it work.

Firstly, you should create a transform for the new type "array":

DS.ArrayTransform = DS.Transform.extend({  deserialize: function(serialized) {    return (Ember.typeOf(serialized) == "array")        ? serialized         : [];  },  serialize: function(deserialized) {    var type = Ember.typeOf(deserialized);    if (type == 'array') {        return deserialized    } else if (type == 'string') {        return deserialized.split(',').map(function(item) {            return jQuery.trim(item);        });    } else {        return [];    }  }});App.register("transform:array", DS.ArrayTransform);

Now, in your model, just use it as another attr:

App.myModel = Ember.Model.extend({    name : DS.attr('string'),    cont : DS.attr('array')}

And we are done. Remember, when adding elements to the array, to use pushObject.

In a controller:

this.get('model.cont').pushObject('new Item');

I hope this helps someone.

I use a raw transform, which looks like this in ember-data revision 11:

DS.RESTAdapter.registerTransform('raw', {    deserialize: function(serialized) {        return serialized;    },      serialize: function(deserialized) {        return deserialized;    }   });

Then, within a model, I do this:

App.MyModel = Ember.Model.extend({    anArray: DS.attr('raw')});

and can use anArray like a regular array anywhere.

Here is an example of creating a custom array type in Ember-Data (version 10):

DS.JSONTransforms.array =  # If the outgoing json is already a valid javascript array  # then pass it through untouched. In all other cases, replace it  # with an empty array.  This means null or undefined values  # automatically become empty arrays when serializing this type.  serialize: (jsonData)->    if Em.typeOf(jsonData) is 'array' then jsonData else []  # If the incoming data is a javascript array, pass it through.  # If it is a string, then coerce it into an array by splitting  # it on commas and trimming whitespace on each element.  # Otherwise pass back an empty array.  This has the effect of  # turning all other data types (including nulls and undefined  # values) into empty arrays.  deserialize: (externalData)->    switch Em.typeOf(externalData)      when 'array'  then return externalData      when 'string' then return externalData.split(',').map((item)-> jQuery.trim(item))      else               return []

Now you can use the custom type in a model attribute:

App.CalenderWeek = DS.Model.extend  selected_days = DS.attr('array')

And now when you fetch a record with:

App.CalendarWeek.find(1)

both of these incoming json records will deserialize correctly into an Array:

{ selected_days: ['Monday', 'Tuesday', 'Saturday'] }

or

{ selected_days: 'Monday, Tuesday, Saturday' }