Explicitly linking controllers with Angular scope objects

Question

Explicitly linking controllers with Angular scope objects

According to the documentation on AngularJS Understanding controllers:

Linking Controllers to Angular Scope Objects

Controllers can be linked to scope objects implicitly through the ngController directive or $route service.

These two methods are commonly used in AngularJS applications.

I found an interesting piece in the Developer Guide / Understanding the Controller Component:

Linking Controllers to Angular Scope Objects

Controllers can be linked to scope objects explicitly using the scope.$new api, or implicitly through the ngController directive or $route service.

In addition to the implicit linkage of controller with scope, there is also a mention of an explicit method using the scope.$new api.

While it's known that scope.$new creates a new [isolated] scope, the connection to explicitly linking the controller with the scope is not clear to me.

It would be helpful to see a practical example and/or more detailed explanation.

javascript angularjs scope

Answer 1

Answer №1

One common use case for this is during testing, when there is a need to directly create and interact with a controller.

An easy way to achieve this is by utilizing the $controller service:

var scope = $rootScope.$new();
var ctrl = $controller(MyAwesomeController, { $scope: scope });

By manipulating the scope variable directly, we can easily check for any effects:

scope.foo = 'bar'
scope.$digest();

expect(scope.bar).toBe('YEAH BABY!!!');

The $controller service not only instantiates a controller with all dependencies injected as expected, but it also allows for passing in a locals hash that can override any dependencies with custom values provided explicitly.

This feature is particularly valuable for testing purposes, as it enables swapping out services with mocks if necessary.

Answer 2

One common use case for this is during testing, when there is a need to directly create and interact with a controller.

An easy way to achieve this is by utilizing the $controller service:

var scope = $rootScope.$new();
var ctrl = $controller(MyAwesomeController, { $scope: scope });

By manipulating the scope variable directly, we can easily check for any effects:

scope.foo = 'bar'
scope.$digest();

expect(scope.bar).toBe('YEAH BABY!!!');

The $controller service not only instantiates a controller with all dependencies injected as expected, but it also allows for passing in a locals hash that can override any dependencies with custom values provided explicitly.

This feature is particularly valuable for testing purposes, as it enables swapping out services with mocks if necessary.

Explicitly linking controllers with Angular scope objects

Linking Controllers to Angular Scope Objects

Linking Controllers to Angular Scope Objects

Answer №1

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