Angular.js "Controller as ..." + $scope.$on

Question

If i'd like to use the "Controller as ..." syntax in Angular, how should I approach things like $scope.$on(...) that i need to put inside the controller?

I get an impression i could do it some other way than the one shown below. Here, to get $scope.$on working i bind "this" to the callback function. I tried to invoke $on on "this" inside the controller but it didn't work.

Could you give me a hint here or if i'm completely messing up, could you point me to some right way to do it? Thanks.

main.js:

angular.module('ramaApp')
.controller('MainCtrl', ['$scope', '$location', function ($scope, $location) {

    this.whereAmINow = 'INDEX';

    $scope.$on('$locationChangeStart', function(event) {

        this.whereAmINow = $location.path();

    }.bind(this));

    this.jumpTo = function(where) { $location.path(where); }
}]);

index.html:

<div ng-controller="MainCtrl as main">

    <p>I am seeing the slide named: {{ main.whereAmINow }}</p>

    <div ng-click="main.jumpTo('/slide1')">Slide 1</div>
    <div ng-click="main.jumpTo('/slide2')">Slide 2</div>
    <div ng-click="main.jumpTo('/slide3')">Slide 3</div>

</div>

Answer 1

As far as I know, you need to inject $scope if you want $scope watchers/methods. ControllerAs is just syntactic sugar to enable to see more clearly the structure of your nested controllers.

Three ideas though which may simplify your code.

1. Use var vm = this, in order to get rid of the bind(this).

   var vm = this;
   vm.whereAmINow = "/";
   
   $scope.$on('$locationChangeStart', function(event) {
       vm.whereAmINow = $location.path();
   });
   
   vm.jumpTo = function(where) {
       $location.path(where);
   }
   

2. The whole whereamINow variable makes sense putting it into the initialization of app aka .run() (before config) since I assume it's a global variable and you don't need to use a $scope watcher/method for it.

3. Another option is to use a factory to make the changes persist, so you simply create a location factory which holds the current active path.