NestJS Introduction 5

Question 1

How does NestJS support both REST and GraphQL in the same project?

Accepted Answer

By using platform adapters — REST via controllers, GraphQL via @nestjs/graphql module

Answer

NestJS has @nestjs/graphql which integrates Apollo or Mercurius, allowing GraphQL resolvers to coexist with REST controllers.

Question 2

What is 'lazy loading' of modules in NestJS used for?

Accepted Answer

Loading modules only when a specific route is hit to improve startup time

Answer

Lazy loading modules with LazyModuleLoader reduces application startup time by initializing modules on demand rather than at boot.

Question 3

Which decorator is used to inject a value by a custom token rather than a class type?

Accepted Answer

@Inject(TOKEN)

Answer

@Inject(TOKEN) allows injecting custom providers registered with a string or Symbol token instead of a class reference.

Question 4

What is a 'global module' in NestJS and how is it declared?

Accepted Answer

A module whose exported providers are available everywhere without importing; declared with @Global()

Answer

@Global() on a module makes its exports available application-wide so other modules don't need to import it explicitly.

Question 5

What does the 'controllers' array in @Module() declare?

Accepted Answer

Classes that handle incoming HTTP requests and define routes

Answer

Controllers listed in the 'controllers' array are instantiated by NestJS and their route handlers are registered with the HTTP adapter.

NestJS Practice Test