AngularJS - Communication Between Controllers

This is an example of how to use a custom service to facilitate communicate between multiple controllers using $rootscope as an event bus.

HTML

<script src="http://code.angularjs.org/angular-1.0.0rc9.js"></script>
<div ng-controller="ControllerZero">
    <input ng-model="message">
    <button ng-click="handleClick(message);">LOG</button>
 
    <div ng-controller="ControllerOne">
        <input ng-model="message2" >
        <button ng-click="handleClick();">LOG 2</button>
    </div>    
</div>

JavaScript

var myModule = angular.module('myModule', []);

function ControllerZero($scope) {
    $scope.handleClick = function(msg) {
        $scope.$emit('handleChild', {message : msg}); 
    };
    
    $scope.$on('updateParent', function(event, args) {
        $scope.message = 'ZERO: ' + args.message;
    });  
}

function ControllerOne($scope) {
    $scope.$on('handleChild', function(event, args) {
        $scope.message2 = 'ONE: ' + args.message;
    });        
    
    $scope.handleClick = function() {
        $scope.$emit('updateParent', {message: $scope.message2});
    };
    
}

ControllerZero.$inject = ['$scope'];

ControllerOne.$inject = ['$scope'];