$watch on rootscope not working, angular

Question

I have a button which toggles admin and client mode. I've put it in on the rootscope so I can access it everywhere.

I'm using the angular-ui directive for toggling.

I've put a watch on this model. But nothing is happening. Any idea what can be wrong?

.run(['$rootScope', '$state', '$stateParams', '$location',
     function ($rootScope, $state, $stateParams, $location) {

         $rootScope.projectMode = 'Client';

         $rootScope.$watch('projectMode', function(){
             var path = $location.path();
             alert("fire") //Only fire ones when the app starts
             if($rootScope.projectMode === 'Client'){
                 var current = 'client'
                 var replace = 'admin'
             } else {
                 var current = 'admin'
                 var replace = 'client'
             }
             var newUrl = path.replace(current, replace)
             $location.url(newUrl);
         })

    }])

Here's my view.

<div class="btn-group">
  <button type="button" class="btn btn-default"  ng-model="projectMode" btn-radio="'Client'">Klient</button>
  <button type="button" class="btn btn-default"  ng-model="projectMode" btn-radio="'Admin'">Admin</button>
</div>

btn-radio is the angular-ui directive for toggling.

I've checked that the $rootScope.projectMode is changing. So it must be something wrong with the $watch.

Answer 1

The real problem is that the projectMode in your view is not the same projectMode on the $rootScope. This is a common problem people have in Angular.

Scopes in Angular are prototypical. If a property isn't found in the current scope, then it looks for the property with the same name in that scope's parent, and so on until it reaches the $rootScope. So, when your view initializes, it may appear that projectMode is whatever you initialized it to on $rootScope.

However, as soon as you change the value of projectMode, it creates a new value on the controller's scope named projectMode, which is not the same as $rootScope.projectMode. So, it makes sense that your $watch isn't fired... The $rootScope value isn't changing, only the controller scope's value is changing.

If you'd like to fix it, simply change projectMode to $root.projectMode everywhere in your HTML. ($root inside HTML is how you reference $rootScope.)