如何将ng-model添加到ChoiceType symfony？

I need to add an ng-model to every choice in my choice list, so I could watch each choice in angularjs. This is my ChoiceType. I tried adding an attr but it only added it, to the whole list not every choice in the list, I also tried adding a choice_attr but it didn't work.

->add('type', ChoiceType::class, [
            'choices'   => Type::getChoices(),
            'multiple'  =>false,
            'expanded'  =>true,
        ])

This is my twig file.

  <div ng-controller="CreditServiceController">
    {{ form_row(form.type) }}

and this is my angular js.

app.controller('CreditServiceController', function ($scope, $timeout) {

$scope.serviceType = "";

$scope.$watch('serviceType', function () {
    console.log('hello');
})