NestJS Basic 3

Question 1

What is the role of the @Module() decorator's 'providers' array?

Accepted Answer

Declares services and other providers available for injection within the module

Answer

The 'providers' array in @Module() registers injectable services that the NestJS IoC container manages.

Question 2

Which decorator allows you to read the entire request body in a NestJS controller method?

Accepted Answer

@Body()

Answer

@Body() extracts the full request payload (body) and passes it to the method parameter.

Question 3

What does the 'imports' array in @Module() do?

Accepted Answer

Makes exported providers from other modules available in the current module

Answer

The 'imports' array brings in other modules, making their exported providers available for injection.

Question 4

In NestJS, pipes are typically used to:

Accepted Answer

Transform and validate incoming request data

Answer

Pipes in NestJS process incoming data — they can transform it (e.g., string to int) or validate it before it reaches the handler.

Question 5

What is the default HTTP server used by NestJS under the hood?

Accepted Answer

Express

Answer

NestJS uses Express as its default underlying HTTP server, though Fastify is also supported.

NestJS Practice Test