How to select AngularJS model on first time load?

I'm using AngularJS to populate a select option list.

And I'm selecting an option by default depending on a field isMandatory. But the problem is I can't get the id of the selected item on first time load.

It works when I change the option.

Please check this plunker code: http://plnkr.co/edit/U2dVeo1vwZZPFKVhPleV?p=preview

I suggest using ng-options:

<select ng-model="selectedItem" ng-options="item.id as item.text for item in list">

and a function to set the initially selected item:

angular.forEach($scope.list, function(item, key){
  if(item.isMandatory) {
    $scope.selectedItem = item.id;
  }
});

Plunker