Services, HTTP & State — Chapter Quiz

Question 1

1

What does @Injectable({ providedIn: 'root' }) do?

ARegisters the service as a global singleton tree-shakable providerBMarks the service for SSR onlyCForces a new instance per componentDAuto-injects the service into every constructor

providedIn: 'root' is the recommended way to register a service. It's a single shared instance and gets tree-shaken if nothing uses it.

Question 2

2

Which function is the modern way to inject a dependency?

Ainject(HttpClient)Bnew HttpClient()C@Inject(HttpClient)Dprovide(HttpClient)

inject() works in class field initializers, constructor bodies, factories, and route guards — wherever an injection context is available.

Question 3

3

What does provideHttpClient(withInterceptors([authInterceptor])) do?

ADefines the HttpClient and registers a functional interceptorBRegisters the HttpClient as a guardCMocks every HTTP callDConfigures a base URL

withInterceptors takes an array of functional interceptors — the modern form. They run on every request and can read, modify, or short-circuit them.

Question 4

4

In the template, how do you display the latest value of users$: Observable<User[]>?

A{{ users$ }}B{{ users$ | async }}C{{ users$.value }}D{{ users$ | sync }}

The async pipe subscribes for you and unsubscribes when the component is destroyed. No manual cleanup needed.

Question 5

5

A computed() signal is re-evaluated when:

AEvery change-detection cycleBYou call its update() methodCOne of the signals it reads changesDA timer fires

computed tracks the signals you read inside it. It only re-runs when one of them changes, and the result is cached.

Question 6

6

effect() is the right place to put side effects that should run when a signal changes.

TTrueFFalse

effect(() => { ... }) reads any signals inside and re-runs when they change. Good for logging, syncing to localStorage, etc. — not for derived values (use computed for those).

Question 7

7

The Angular API that pairs a signal with an async data source is ___.

resource() (and rxResource) takes a request signal plus a loader and exposes status, value, error as signals.

Question 8

8

Which are common state-management approaches in Angular?

Select all that apply.

Pick the simplest that fits. Lots of apps never need NgRx; a shared service with signals is enough. NgRx and SignalStore shine when state coordination across many features gets hairy.

Test what you learned.