Routes & Decorators — Series 2

Preview — 3 of 10 questions

What path does this handler respond to?

javascript

@Controller()
export class AppController {
  @Get('health')
  health() { return { status: 'ok' }; }
}

A/app/health, derived from the controller's class name

BNothing — a prefix is mandatory, so the route is never registered

C/health, because an empty @Controller() contributes no prefix

DBoth /health and /, since an empty prefix also registers a root route

How does Nest handle the returned promise?

javascript

@Get()
async findAll(): Promise<Cat[]> {
  return this.catsService.findAll();
}

AIt awaits the promise and serialises the resolved value as the response body; a rejection is routed to the exception layer

BIt serialises the promise object itself, producing {} in the response

CIt requires @Res() to be injected before a handler may be async

DIt converts the handler into a Server-Sent Events stream

What does the @Headers('x-api-key') decorator return?

javascript

@Get('profile')
getProfile(@Headers('x-api-key') apiKey: string) { /* ... */ }

AThe raw header block as a single string, exactly as it arrived on the wire

BAn array of every header whose name starts with x-

Cundefined unless the header name is registered in main.ts

DThe value of that one header, looked up case-insensitively; omitting the argument returns the whole headers object

Answer all 10 questions (7 more), see explanations for every answer, and track your score.