AngularJS transformResponse

Question

In angularjs resource, I would like to convert my json data into JS objects

//Complex object with inheritance chain
function Car(year, make){
    this.make = make;
    this.year = year;
}


var carResource = $resource("/api/car/id", {id: '@id'},
    {
        get: {
            method: 'GET',
            transformResponse: function(data, headersGetter){
                return new Car(data.make, data.year);
            }
        }
    }
)

However this does not seem to be happening

What I am getting back is a $resource object meaning that the properties make and year are set correctly, however the prototype of the returned object points to $resource

Is there a way where I can map my json data directly to my own objects?

Or will I have to write my own 'resource' implementation?

Answer 1

transformResponse is executed on $http level.

When you customise $resource actions with custom config object, that object is actually passed on to the underlying $http service. So if you specify a transformResponse callback, it will be executed on $http level, and the results of your transformation will be passed back on to $resource.

$resource service will instantiate new object from your response data (which is already transformed by the transformResponse callback) and this new object will be an instance of the $resource itself.

So, your car object will be an instance of the Car, but only for a moment, until it's properties are copied into a new $resource object.

Here's a simplistic view of the process:

1. $resource service initiates request
2. $http service sends request and receives the response
3. $http service transforms the response (response is now instance of Car)
4. $resource service receives the transformed response (from $http)
5. $resource service makes an instance of itself using transformed response properties (result is now instance of $resource)

Anyway, I don't recommend decorating or extending the $resource service, because it's simpler to write your own implementation using $http service.