Angular Scope Usage

Question

I am a beginner in AngularJS.

I am working through some code of an expert. I would like to customize the directive and learn something.

The expert always insert:

this.scope = $scope;

in the first line of every controller.

What's the point of this statement, if you later always just use $scope.

• BiAiB: This means your app manipulates controller instances. You can sometimes be passed a controller instance: when using "Controller as" syntax see docs.angularjs.org/api/ng/directive/ngController (ctrl-as-exmpl). Also, when defining controller for directives. I'm not knowledgeable about the advantages of doing things this way so I'll just leave this as a comment.

Answer 1

this pointer was referring to $scope instead of the controller.

this

• When the controller constructor function is called, this is the controller.
• When a function defined on a $scope object is called, this is the "scope in effect when
  the function was called". This may (or may not!) be the $scope that the function is defined on. **So, inside the function, this and $scope may not be the same.

$scope

• Every controller has an associated $scope object.
• A controller (constructor) function is responsible for setting model properties and functions/behavior on its associated $scope.
• Only methods defined on this $scope object (and parent scope objects, if prototypical inheritance is in play) are accessible from the HTML/view. E.g., from ng-click, filters, etc.

courtesy of Mark Rajcok taken from How does 'this' and $scope work in AngularJS controllers

without this

app.controller('MyCtrl', function($scope){
 $scope.doStuff = function(){
 //Really long function body
 };
});

with this

var MyCtrl = function($scope){
 var _this = this;
 $scope.doStuff = function(){
 _this.doStuff();
 };
};
MyCtrl.prototype.doStuff = function(){
 //Really long function body
};
MyCtrl.$inject = ['$scope'];
app.controller('MyCtrl', MyCtrl);

• Johannes: Thanks for the comprehensive answer. I will continue using just $scope until I really need this.