Question

In the “wire up a backend” demo code from the angularjs site they set up a db call. From what I can tell they’re extending the update function in order to add some extra parameters needed by the mongolab api.

angular.module('mongolab', ['ngResource']).
factory('Project', function($resource) {
  var Project = $resource('https://api.mongolab.com/api/1/databases' +
      '/angularjs/collections/projects/:id',
      { apiKey: '4f847ad3e4b08a2eed5f3b54' }, {
        update: { method: 'PUT' }
      }
  );

  Project.prototype.update = function(cb) {
    return Project.update({id: this._id.$oid},
        angular.extend({}, this, {_id:undefined}), cb);
  };

Then they call the update property like this:

$scope.save = function() {
$scope.project.update(function() {
  $location.path('/');
});

I’ve tried using this code to build a demo app using a local development server so I’ve omitted extending the update property as I don’t need the extra $oid parameter. What I do need is to specify that the update method should use PUT. My code is like this:

var Unit = $resource('http:/localhost/api/unit/:id', {id:'@Unit_Id'},
{'update': { method: 'PUT' }}); 

And then calling it like this:

$scope.save = function () {
    $scope.unit.update(function () {
        $location.path('/unitlist');
    });

But What I’ve discovered is that the code only runs with a dollar sign in front of update like this:

    $scope.save = function () {
    $scope.unit.$update(function () {
        $location.path('/unitlist');
    });

So here are my questions:

1. In the demo code, where is “update” actually added to the Project variable? As a parameter in $resource or using prototype to extend Project?
2. Why is update undefined in my code unless I prefix $ when I call it?

Answer 1

Ok, here it is from the docs

The action methods on the class object or instance object can be
invoked with the following parameters: HTTP GET “class” actions:
Resource.action([parameters], [success], [error]) non-GET “class”
actions: Resource.action([parameters], postData, [success], [error])
non-GET instance actions: instance.$action([parameters], [success],
[error])

So, when you when you extend the class (prototype), call it without the $ like normal, but when you add an action as a parameter of $resource prefix $.