Angular-recursion, как добавить счетчик количества вложенностей?

angular.module('myModule', ['RecursionHelper']).directive("tree", function(RecursionHelper) {
    return {
        restrict: "E",
        scope: {family: '=', level='@'},
        template: 
        '<p>{{ family.name }}{{test }}</p>'+
            '<ul>' + 
                '<li ng-repeat="child in family.children">' + 
                    '<tree family="child" level="{{(level)?level + 1: 1}}"></tree>' +
                '</li>' +
            '</ul>',
        compile: function(element) {
            return RecursionHelper.compile(element, function(scope, iElement, iAttrs, controller, transcludeFn){
            });
        }
    };
});