Angular Web Framework Angular Advanced Practice 2

Question 1

Which Angular CDK feature allows you to create custom overlays that are rendered in a portal outside the normal DOM tree?

Accepted Answer

Portal

Answer

The CDK Portal module lets you render components or templates into a PortalOutlet that lives outside the component's normal DOM position.

Question 2

What is the purpose of the `APP_INITIALIZER` token in Angular?

Accepted Answer

To run initialization logic before the app bootstraps

Answer

APP_INITIALIZER accepts factory functions that return Promises or Observables; Angular waits for them to complete before rendering the root component.

Question 3

In Angular's Ivy renderer, what replaces the old NgFactory files used by View Engine?

Accepted Answer

Locality principle compilation with ɵcmp and ɵfac static fields

Answer

Ivy uses locality: each class carries its own compiled metadata (ɵcmp, ɵfac, ɵmod) as static fields, eliminating the need for separate NgFactory files.

Question 4

Which RxJS operator is best suited for switching to a new Observable while cancelling the previous in-flight request, such as in a search typeahead?

Accepted Answer

switchMap

Answer

switchMap unsubscribes from the previous inner Observable and subscribes to the new one, which cancels any ongoing HTTP request for prior keystrokes.

Question 5

What does the `trackBy` function in `*ngFor` receive as its two arguments?

Accepted Answer

index and item

Answer

The trackBy callback receives the loop index and the current item, and should return a unique identifier so Angular avoids re-rendering unchanged DOM nodes.

Angular Web Framework Practice Test

Angular Web Framework Practice Test

Angular Web Framework Angular Advanced Practice 2