Angularjs trigger country state dependency

Angularjs trigger country state dependency

Can someone please help me make my example of Country/State drop down
dependency work?
I intentionally created JSON in this way because I want the dependency to
be generic, so I would be able to apply it on any drop down while using
only Meta Data and not HTML.
Here's a link to see an example of the code in JSFidlle
HTML
Country:<select data-ng-model="Countries" data-ng-options="country.id as
country.name for country in Countries.items">
<option value="">Please select a country</option>
</select>
State: <select data-ng-model="currentItem" data-ng-options="item.id as
item.name for item in currentStates.items">
<option value="">Please select a state</option>
</select>
JavaScript Code:
function Controller($scope) {
var Countries = {
"id": "field10",
"items": [{
"id": "10",
"StateGroupID":"0",
"name": "United State"
},
{
"id": "2",
"StateGroupID":"1",
"name": "Canada"
}]
};
var States =
{ "id": "field20",
"StateGroups": [{
"items": [{ "id": "1",
"name": "Alabama"
},
{
"id": "2",
"name": "Alaska"
},
{ "id": "3",
"name": "Arizona"
},
{ "id": "4",
"name": "California"
}]},
[{ "id": "201",
"name": "Alberta"
},
{
"id": "202",
"name": "British Columbia"
},
{
"id": "303",
"name": "Manitoba"
},
{
"id": "304",
"name": "Ontario"
}]]
};
$scope.Countries = Countries;
$scope.currentStates = States.StateGroups[0];
$scope.$watch('currentStates', function(value, oldValue){
//alert(value);
//alert(JSON.stringify(value));
//$scope.currentStates = (value == "10") ? States.StateGroups[0] :
States.StateGroups[1];
});
}