Angular: Update service and share data between controllers

Question

I'm using a service to grab some data from an API:

angular.module('myApp', [])
.factory('myService', function($q, $timeout) {
    var getMessages = function() {
        var deferred = $q.defer();

        $timeout(function() {
            deferred.resolve('Hello world!');
        }, 2000);

        return deferred.promise;
    };

  return {
    getMessages: getMessages
  };

});

And I use these data in multiple controllers.

function ControllerA($scope, myService) {
    $scope.message = myService.getMessages();
    $scope.updateMessage = function(){
        $scope.message = 'Hello Max';        
    };
}

function ControllerB($scope, myService) {
    $scope.message = myService.getMessages();
    $scope.$watch('message', function(){
       // 'Hello Max'
    }, true);
}

I would like to update the data in every controller, but when I change the $scope.message in the ControllerA, it doesn't fire a change in the ControllerB.

EDIT: The thing is that I would like to avoid using "$broadcast" and "$on".

Any ideas?

Here's a jsfiddle: http://jsfiddle.net/Victa/McLQD/

Answer 1

You can use $broadcast to broadcast an event to the rootScope and use $on to define listener to listen to this specific event.

function ControllerA($scope, myService, $rootScope) {
    $scope.message = myService.getMessages();
    $scope.updateMessage = function () {
        $scope.message = 'Hello Max';

        $rootScope.$broadcast("HelloEvent", {
            msg: $scope.message
        });
    };
}

function ControllerB($scope, myService, $rootScope) {
    $scope.message = myService.getMessages();

    $rootScope.$on("HelloEvent", function (event, message) {
        $scope.message = message.msg;
    });
}

Updated:

I got the above solution just before you updated your question. If you don't want to use $broadcast or $on, you can share the object via $rootScope like this

function ControllerA($scope, myService, $rootScope) {
    $scope.message = myService.getMessages();
    $scope.updateMessage = function () {
        $scope.message = 'Hello Max';
        $rootScope.message = 'Hello Max';
    };
}

function ControllerB($scope, myService, $timeout, $rootScope) {
    $scope.message = myService.getMessages();

    $rootScope.$watch('message', function (oldV, newV) {
        if(oldV === undefined && oldV === newV) return;
        $scope.message = $rootScope.message;
    });
}

Demo using broadcast Demo without using broadcast