Angular JS orderBy not working using dropdown - angularjs

Question

i am trying to do orderBy using dropdown value, but its not working :(
CODE:
var app = angular.module('myApp', []);
app.controller('myCtrl', function ($scope) {
$scope.datas = [{
"id": "1",
"name": "name area 1"
}, {
"id": "2",
"name": "name area 2"
}, {
"id": "3",
"name": "name area 3"
}, {
"id": "4",
"name": "name area 4"
}];
$scope.dropdown = [{
"title": "Newest first",
"value": "true"
}, {
"title": "Oldest first",
"value": "reverse"
}];
});
HTML:
<div ng-app="myApp">
<div ng-controller="myCtrl">
<ul ng-repeat="rows in datas | orderBy: 'id':orderByData">
<li>{{rows.id}} : {{rows.name}}</li>
</ul>
<select ng-model="orderByData" ng-options="x.value as x.title for x in dropdown"></select>
</div>
</div>
DEOM JS BIN

Answer 1

Why you use reverse?
Please use false instead reverse and it should work fine.
$scope.dropdown = [{
"title": "Newest first",
"value": "true"
}, {
"title": "Oldest first",
"value": "false"
}];

Answer 2

You don't need reverse parameter here. Instead you can do something like this:
<ul ng-repeat="rows in datas | orderBy: getSort()">
<li>{{rows.id}} : {{rows.name}}</li>
</ul>
Where getSort is defined as:
$scope.getSort = function() {
return $scope.orderByData ? 'id' : '-id';
};
Basically you want sort part to look like orderBy: 'id' or orderBy: '-id'.
Demo: http://jsbin.com/pepureta/1/edit?html,js,output