How to represent arrays within ember-data models?

Question

Is it necessary to use DS.hasMany pointing to a DS.Model when a model contains an array? Even if the array elements are not really models (no IDs o

Answer 1

A bit late to the game here but here's a jFiddle I found that is a simple implementation of declaring a new array codec

http://jsfiddle.net/Nook/ab2Xf/

Answer 2

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' }

Answer 3

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.

Answer 4

If you absolutely need a custom data structure to be exchanged with your server, you can enrich DS.attr.transforms and declare a new array codec, for example.

See source code for existing attribute codecs implementation. It is a good place to start adding your own.

Answer 5

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.

Answer 6

In Ember Data 1.0.0 Beta, one has been given the ability to "register" his or her custom transform "subclass". I'd prefer to refer to it as an extended DS.Transform object.

DS.ArrayTransform = DS.Transform.extend({
    deserialize: function(deserialized) {
        // ...
        return deserialized;
    },

    serialize: function(serialized) {
        // ...
        return serialized;
    }
});

App.register('transform:array', DS.ArrayTransform);