When should I use markForCheck?

markForCheck is needed when the ChangeDetectionStrategy of your component is OnPush which means only run the change detection if any of the below happens. One of the @inputs of the component has been completely replaced with a new value.

Correspondingly, what is the use of ChangeDetectorRef?

ChangeDetectorReflink. Base class for Angular Views, provides change detection functionality. A change-detection tree collects all views that are to be checked for changes.

Additionally, what is ChangeDetectionStrategy? ChangeDetectionStrategylink The strategy that the default change detector uses to detect changes. When set, takes effect the next time change detection is triggered.

Regarding this, what triggers change detection in angular?

Automatic change detection with zones As opposed to React, change detection in Angular can be triggered completely automatically as a result of any async event in a browser. This is made possible by using the library called zone. js that introduces a concept of zones.

What is ChangeDetectorRef in angular?

ChangeDetectorRef. markForCheck instructs Angular that this particular input should trigger change detection when mutated.

What is AfterViewInit?

AfterViewInitlink A lifecycle hook that is called after Angular has fully initialized a component's view. Define an ngAfterViewInit() method to handle any additional initialization tasks.

What is Zonejs?

Zonejs is one of the core library used in Angularjs 2. Zonejs is to maintain contextual execution for single or multi-leveled asynchronous methods. So, it means it helps to keep track of the parent context of currently executing asynchronous method. Example - Zone.

What is angular life cycle?

In Angular, every component has a life-cycle, a number of different stages it goes through. There are 8 different stages in the component lifecycle. Every stage is called as lifecycle hook event. After executing the constructor, Angular executes its lifecycle hook methods in a specific order.

How do you use ngOnInit?

It is invoked only once when the directive is instantiated. Mostly we use ngOnInit for all the initialization/declaration and avoid stuff to work in the constructor. The constructor should only be used to initialize class members but shouldn't do actual "work".

How does angular update the DOM?

It basically takes the current value passed from the updateRenderer function and compares it to the value from the previous change detection. A View holds old values in the oldValues property. If the value changed Angular uses the updated value to compose a string and update the DOM using a renderer.

What is OnPush change detection?

Angular offers another change detection strategy: it's called OnPush and it can be defined on any component. With this strategy, the template of the component will only be checked in 2 cases: one of the inputs of the component changed (to be more accurate, when the reference of one of the inputs changes);

How does AngularJS application work?

When AngularJS starts your application, it parses and processes this new markup from the template using the compiler. The loaded, transformed and rendered DOM is then called the view. The first kind of new markup are the directives. They apply special behavior to attributes or elements in the HTML.