Understanding AngularJS $rootScope and $scope

 Print 
  Author : Shailendra Chauhan
Posted On : 10 Sep 2014
Total Views : 63,238   
Updated On : 26 Sep 2016
 

Scope is an object that refers to the application model. It acts as a context for evaluating expressions. Typically, it acts as a glue between controller and view. Scopes are hierarchical in nature and follow the DOM structure of your angular app. AngularJS has two scope objects: $rootScope and $scope. Let's have a look, how they work.

$scope

A $scope is a JavaScript object which is used for communication between controller and view. Basically, $scope binds a view (DOM element) to the viewmodel and functions defined in a controller.

$rootScope

The $rootScope is the top-most scope. An app can have only one $rootScope which will be shared among all the components of an app. Hence it acts like a global variable. All other $scopes are children of the $rootScope.

AngularJS : $rootScope and $scope with example

<!doctype html>
<html>
<body ng-app="myApp">
<div ng-controller="Ctrl1" style="border:2px solid blue; padding:5px">
 Hello {{msg}}!
 <br />
 Hello {{name}}!
 (rootScope)
</div>
<br />
<div ng-controller="Ctrl2" style="border:2px solid green; padding:5px">
 Hello {{msg}}!
 <br />
 Hey {{myName}}!
 <br />
 Hi {{name}}! (rootScope)
</div>
<script src="lib/angular.js"></script>
<script>
 var app = angular.module('myApp', []);

 app.controller('Ctrl1', function ($scope, $rootScope) {
 $scope.msg = 'World';
 $rootScope.name = 'AngularJS';
 });

 app.controller('Ctrl2', function ($scope, $rootScope) {
 $scope.msg = 'Dot Net Tricks';
 $scope.myName = $rootScope.name;
 });
</script>
</body>
</html>

How it works...

Note

  1. When you use ng-model with $rootScope objects then AngularJS updates those objects under a specific $scope of a controller but not at global level $rootScope.

  2. Create a private $scope for each controller to bind it to the view.

What do you think?

I hope you will enjoy the AngularJS: $rootScope and $scope while developing your app with AngularJS. I would like to have feedback from my blog readers. Your valuable feedback, question, or comments about this article are always welcome.



Free Interview Books
 
COMMENTS
SUBSCRIBE TO OUR YOUTUBE CHANNEL
 
 
 
LIKE US ON FACEBOOK
 
+