MEAN Angular Components and Services

Question 1

What decorator is used to define a service that can be injected into Angular components?

Accepted Answer

@Injectable()

Answer

@Service()

Answer

@Provider()

Answer

@Inject()

Question 2

What is Angular's Change Detection strategy `OnPush` used for?

Accepted Answer

Improves performance by only checking a component when its inputs change or events fire

Answer

Forces immediate UI updates on every data change

Answer

Disables change detection for a component entirely

Answer

Pushes data changes to a remote server

Question 3

Which Angular lifecycle hook is called after the component's view and child views are initialized?

Accepted Answer

ngAfterViewInit

Answer

ngOnInit

Answer

ngAfterContentInit

Answer

ngViewReady

Question 4

What is the purpose of Angular's `@ViewChild` decorator?

Accepted Answer

Gets a reference to a child component, directive, or DOM element in the template

Answer

Creates a child component programmatically

Answer

Observes changes in child component properties

Answer

Passes data down to a child component

Question 5

What does the Angular `async` pipe do in a template?

Accepted Answer

Subscribes to an Observable or Promise and returns the latest emitted value automatically

Answer

Makes template expressions run asynchronously

Answer

Delays rendering until all data is loaded

Answer

Converts callbacks to Promises in templates

Question 6

What is the difference between `@Input()` and `@Output()` decorators in Angular?

Accepted Answer

@Input() receives data from parent; @Output() emits events to the parent with EventEmitter

Answer

@Input() sends data to the server; @Output() receives server responses

Answer

@Input() is for template binding; @Output() is for service calls

Answer

@Input() handles form inputs; @Output() submits form data