Not able to figure out what the bug in this code is.I've tried to only post the relevant parts of the code here.
Controller
myApp.controller('MessageCtrl', function ($scope, notificationService, $rootScope) {
$scope.notificationService = notificationService;
$scope.msgCount = 0;
$scope.notificationService.subscribe({channel : 'my_channel'});
$rootScope.$on('pubnub:msg',function(event,message){
$scope.msgCount = $scope.msgCount + 1;
//$scope.$digest();
});
});
My Notification Angular Service
myApp.factory('notificationService',['$rootScope', function($rootScope) {
var pubnub = PUBNUB.init({
publish_key : '..',
subscribe_key : '..'
});
var notificationService = {
subscribe : function(subscription) {
pubnub.subscribe({
channel : subscription.channel,
message : function(m){
$rootScope.$broadcast('pubnub:msg', m);
}
});
}
};
return notificationService;
}]);
And the template :
<div>
Count = {{msgCount}}
</div>
The problem :
Using console logs & using karma tests I have confirmed that the $rootScope.$on
method in MessageCtrl
is getting called when I do a $broadcast
from Notification Service. And that the msgCount
variable is getting incremented. However, I don't see the updated value being reflected in the template without running a $scope.$digest()
. I am pretty sure I shouldn't be needing to have to call $scope.$digest
, ie Angular should be providing me this binding.
Interestingly, when I tried a $rootScope.$broadcast
from another controller, the msgCount
in the template got incremented without having to call $scope.$digest
().
Can anyone kindly help me here. Thank you.
Update
Thanks to Peter and looking at the google group discussion, wrapping the $broadcast
in an $apply
did the trick.
$rootScope.$apply(function(){
$rootScope.$broadcast('pubnub:question', m);
});
It seems that your $broadcast
happens outside AngularJS and you need to notify your app about it with calling $apply()
, but better do it in the notificationService
.
As for $broadcast and $on trigger a apply/digest you can read in this post. Brief overview of AngularJs source files make me sure that $broadcast does not auto-apply changes (look here ). $broadcast just calling listeners and nothing else.
Please, take a look at this simple example on jsFiddle .
The template
<div ng-controller="myCtrl">
<p>Count: {{ count }}</p>
<button ng-click="fireEvent()">Fire Event</button>
</div>
The controller
angular.module("app", [])
.controller('myCtrl', function($scope, $rootScope, notificationService) {
$scope.count = 0;
notificationService.subscribe();
$rootScope.$on('event', function() {
console.log("event listener");
$scope.count++;
});
$scope.fireEvent = function() {
// it is ok here due to ngClick directve
$rootScope.$broadcast('event', true);
};
})
And factory
.factory('notificationService',['$rootScope', function($rootScope) {
var notificationService = {
subscribe : function() {
setInterval(function(){
console.log("some event happend and broadcasted");
$rootScope.$broadcast('event', true);
// angular does not know about this
//$rootScope.$apply();
}, 5000);
}
};
return notificationService;
}]);
Of course in both cases you will see that event listener fires, but ngClick fires $digest and your notificationService
does not.
Also you can get some info about sources that will start the digest cicle in this nice answer https://stackoverflow.com/a/12491335/1274503