Ember Data: option to not use identity map and ignore relationship - ember.js

Question

One of the powers of Ember Data is that it uses identity maps to ensure that there is a single source of truth, but to ensure that this happens, it's very prescriptive on how the models need to be configured and what the server needs to return. But sometimes in a mostly read-only app, the single source of truth is not necessary and changing the API on the server is more work than necessary. In these instances, is there a way to tell Ember Data to just accept an array or object as is and don't try to map it to an identity map? Here's a quick example using widget and category:
This is what Ember Data wants us to do:
App.Widget = DS.Model.extend({
name: DS.attr('string'),
categories: DS.hasMany('category')
});
App.Category = DS.Model.extend({
name: DS.attr('string')
});
And Ember Data wants us to return this from the server:
{
"widget": {
"name":"Awesome Device!",
"categories":[1,2]
},
"categories":[
{id:1,"name":"Device"},
{id:2,"name":"Fun"}
]
}
But if this is a mostly a read-only app where the categories won't change, is there a way to tell Ember Data to treat categories as just simple value objects?
App.Widget = DS.Model.extend({
name: DS.attr('string'),
categories: DS.attr('array') // any way to do something like this?
});
Then the server can simply return this:
{
"widget": {
"name":"Awesome Device!",
"categories": [
{ id: 1, "name": "Device" },
{ id: 2, "name": "Fun" }
]
}
}

Answer 1

You can create your own transform, some common ones that you might attempt are raw, or array. I generally gravitate toward raw when I'm lazy
App.RawTransform = DS.Transform.extend({
deserialize: function(serialized) {
return serialized;
},
serialize: function(deserialized) {
return deserialized;
}
});
App.register("transform:raw", App.RawTransform);
App.Widget = DS.Model.extend({
name: DS.attr('string'),
categories: DS.attr('raw')
});
http://emberjs.com/api/data/classes/DS.Transform.html