AngularJS : How to create a two-way data binding between two isolated controllers and a shared service?

Question

I am trying to create a two-way data binding between two isolated controllers and a shared service (which provides another isolated scope):

app.factory("sharedScope", function($rootScope) {
    var scope = $rootScope.$new(true);
    scope.data = "init text from factory";
    return scope;
});

app.controller("first", function($scope, sharedScope) {
    $scope.data1 = sharedScope.data;
});

app.controller("second", function($scope, sharedScope) {
    $scope.data2 = sharedScope.data;
});

Fiddle: http://jsfiddle.net/akashivskyy/MLuJA/

When the application launches, data1 and data2 are correctly updated to the init text from factory , but later, if I change any of them, those changes are not reflected throughout those three scopes.

How can I bind them?

PS If there's a better way than returning a scope and still having access to event and observing functionalities (without basically re-writing them), let me know. :)

Answer 1

Fixed it. References will be lost if you are using primitives, as in your fiddle.

Check this:

Updated fiddle

app.factory("sharedScope", function($rootScope) {
    var scope = $rootScope.$new(true);
    scope.data = {text: "init text from factory"};
    return scope;
});

app.controller("first", function($scope, sharedScope) {
    $scope.data1 = sharedScope.data;
});

app.controller("second", function($scope, sharedScope) {
    $scope.data2 = sharedScope.data;
});

Answer 2

Yet another fun bit: In this case, you don't need to inject $scope or $rootScope. The following code works if you utilize Controller As. Check the Fiddle

var app = angular.module("app", []);

app.factory("sharedScope", function() {
    var _this = this;
    _this.data = {text: "init text from factory"};
    return _this;
});

app.controller("first", function(sharedScope) {
    var _this = this;
    _this.data1 = sharedScope.data;
});

app.controller("second", function(sharedScope) {
    var _this = this;
    _this.data2 = sharedScope.data;
});

For even more fun, consider controllers, services, and factories as classes. More Fiddles

var app = angular.module("app", []);

var SharedScope = function(){
    var _this = this;
    _this.data = {text: "init text from factory"};
    return _this;
};

app.factory("sharedScope", SharedScope);

var First = function(sharedScope){
    var _this = this;
    _this.data1 = sharedScope.data;
};

var Second = function(sharedScope){
    var _this = this;
    _this.data2 = sharedScope.data;
};

First.$inject = ['sharedScope'];
Second.$inject = ['sharedScope'];

app.controller("first", First);              
app.controller("second", Second);

I've been playing at implementing Josh Carroll's Guidelines to Avoid "Scope Soup"

Answer 3

JavaScript passes objects by reference, so all scopes will point to the same object. Why not just do this?

app.factory("sharedData", function() {
    return {data: "init text from factory"};
});

app.controller("first", function($scope, sharedData) {
    $scope.sharedData = sharedData;
});

app.controller("second", function($scope, sharedData) {
    $scope.sharedData = sharedData;
});

and in your view:

<p>{{sharedData.data}}</p>