Add a custom method to $resource in Angular JS - angularjs

Question

I have written a custom method to do a call to my API passing some extra parameters, but I get the following error:
TypeError test.testing is not a function.
I followed the code in here: https://docs.angularjs.org/api/ngResource/service/$resource
This is the code I use, $save for example is working fine.
I am using version 1.4.1.
services.factory('Calendar',function($resource){
return $resource('/api/calendar/:id',{
update: {
method: 'PUT'
},
testing: {
method: "POST", params:{charge:true}
}
});
});
function( $scope, Calendar ) {
var test = new Calendar();
test.title = "hello";
test.$testing();
...
}

Answer 1

The reason is because you haven't quite followed the example in the docs. See:
angular.module('testApp', [])
.factory('CreditCard', creditCard)
.factory('Calendar', calendar);
function creditCard() {
return $resource('/user/:userId/card/:cardId',
{userId:123, cardId:'#id'}, {
charge: {method:'POST', params:{charge:true}}
});
}
function calendar() {
return $resource('/api/calendar/:id',
{id: 200},
{
update: {
method: 'PUT'
},
testing: {
method: "POST", params:{charge:true}
}
});
}
As you can see I added that second object argument {id:200} that tells the ng-resource that in order to fill out /api/calendar/:id correctly it needs to pull the property id from that object and use its value.