Change detection API Underlying architecture in Angular

Question

I was going through this article and was confused about how the change detection action works. https://vsavkin.com/change-detection-in-angular-2-4f216b855d4c

The con

Answer 1

It's a quite broad question - these two articles should give you a good understanding:

• Angular’s $digest is reborn in the newer version of Angular
• Everything you need to know about change detection in Angular

Question 1: Is it that there is an observer or is it an event listener?

Question 2: Does it mean that there is an active change detector object for every component whether we use changeDetectorStartegy.onPush or .Defau

No, change detector is not a listener. Each component in Angular is represented as a view. Hence the application is a tree of views. When you inject ChangeDetectorRef in your component you're essentially injecting a wrapper around this view. Each view has a state which tells whether bindings on this view should be checked. OnPush simply sets this state to disabled so no checks are performed for the view/component. If the bindings change, then Angular sets the state to CheckOnce so that a view is checked only once until the next time the bindings change.

Question 3: What is the impact of these change detector objects in each component implementation if I have 1000 component objects within Angular application? Especially for the memory profile of the application

Question 4: How do I manage it so that it does not impact the memory profile of the application in the browser

As I explained above, there is no such thing as a separate change detector. It's a wrapper around a view. Views exist anyways since it is how Angular represents components tree under the hood.

Is there a place/resource where I can get the lifecycle of the change detector and ngZone associated?

There is no such thing as a lifecycle for change detector.