do not working controllerAs in the component

Question

I made some modifications to the way the component was created.

The code looks like:

1. Question is why I should define var navbar = this; pose class ComponentCtrl If I have defined controllerAs : 'navbar' ?

2. Second question is so, if I have in this way I have written the controller, always I should define variables pose class ComponentCtrl to have variable global??

   (function () {
   
    var navbar = this;
   
   class ComponentCtrl {
   constructor() { };
   
   
   $onInit() { 
     navbar.toggle = false;
   };
   
   
   activeMenu(name, $event) {
     console.log(name, navbar.toggle);
   
     if (navbar.toggle === true && navbar.name == name) {
       navbar.toggle = !navbar.toggle;
     }
     else if (navbar.toggle === false) {
       navbar.toggle = !navbar.toggle;
     }
     navbar.name = name;
   };
   };
   
   var MyComponent = {
   bindings: {
     user: '<'
   },
   controller: ComponentCtrl,
   controllerAs: 'navbar',
   templateUrl: '/navbar/index.html'
   };
   
   angular.module('app.navbar').component('navbar', MyComponent);
   })();