NestJS Quiz ( Beginner ) - All Questions

This beginner-level NestJS quiz is designed for developers starting with NestJS framework. It covers core fundamentals such as modules, controllers, services, decorators, dependency injection, and basic architecture—perfect for practice and entry-level backend interviews.

Question 1: What is NestJS?

A frontend framework
A backend framework for Node.js
A database
A testing library

Explanation: NestJS is a backend framework built on top of Node.js.

Question 2: NestJS is primarily written in which language?

JavaScript
Python
TypeScript
Java

Explanation: NestJS is written in TypeScript.

Question 3: Which architecture pattern does NestJS follow?

MVC
Monolithic
Microkernel
Layered

Explanation: NestJS follows the MVC-inspired architecture.

Question 4: Which company created NestJS?

Google
Facebook
Microsoft
Independent open-source project

Explanation: NestJS is an open-source framework created by Kamil Myśliwiec.

Question 5: Which command creates a new NestJS project?

nest start
nest new
nest create
nest init

Explanation: nest new creates a new NestJS project.

Question 6: What is a module in NestJS?

A database connection
A logical grouping of application components
A UI component
A middleware

Explanation: Modules group related controllers and providers.

Question 7: Which decorator defines a module?

@Controller()
@Injectable()
@Module()
@Service()

Explanation: @Module() defines a NestJS module.

Question 8: What is the root module of a NestJS application?

MainModule
CoreModule
AppModule
RootModule

Explanation: AppModule is the root module.

Question 9: What is a controller responsible for?

Business logic
Handling HTTP requests
Database operations
Application startup

Explanation: Controllers handle incoming HTTP requests.

Question 10: Which decorator defines a controller?

@Module()
@Controller()
@Injectable()
@Route()

Explanation: @Controller() marks a class as a controller.

Question 11: What is a service in NestJS?

UI handler
Reusable business logic provider
Routing file
CLI command

Explanation: Services contain reusable business logic.

Question 12: Which decorator makes a class a provider?

@Controller()
@Module()
@Injectable()
@Provider()

Explanation: @Injectable() marks a class as a provider.

Question 13: What does dependency injection do in NestJS?

Creates routes
Manages database schema
Supplies required dependencies automatically
Handles HTTP responses

Explanation: Dependency injection provides required class dependencies.

Question 14: Which file bootstraps the NestJS application?

app.module.ts
main.ts
index.ts
server.ts

Explanation: main.ts bootstraps the NestJS app.

Question 15: Which HTTP adapter does NestJS use by default?

Koa
Hapi
Fastify
Express

Explanation: NestJS uses Express by default.

Question 16: Which decorator handles GET requests?

@Post()
@Put()
@Get()
@Request()

Explanation: @Get() handles HTTP GET requests.

Question 17: Which decorator handles POST requests?

@Send()
@Create()
@Post()
@Push()

Explanation: @Post() handles HTTP POST requests.

Question 18: How are route parameters accessed?

@Body()
@Query()
@Param()
@Route()

Explanation: @Param() extracts route parameters.

Question 19: Which decorator accesses request body data?

@Param()
@Query()
@Body()
@Req()

Explanation: @Body() extracts request body.

Question 20: Which decorator accesses query parameters?

@Query()
@Body()
@Param()
@Header()

Explanation: @Query() extracts query parameters.

Question 21: What is middleware in NestJS?

UI logic
Function executed before route handler
Database validator
CLI feature

Explanation: Middleware runs before request reaches controller.

Question 22: Which interface is used to create middleware?

NestMiddleware
MiddlewareHandler
ExpressMiddleware
HttpMiddleware

Explanation: NestMiddleware is used to define middleware.

Question 23: What is a provider in NestJS?

A routing rule
A reusable injectable class
A module only
A CLI tool

Explanation: Providers are injectable classes.

Question 24: Which decorator marks a route as public?

@Public()
@Open()
@Allow()
None by default

Explanation: NestJS does not have a built-in public decorator by default.

Question 25: Which feature enables request validation?

Pipes
Guards
Interceptors
Filters

Explanation: Pipes are used for validation and transformation.

Question 26: Which pipe is commonly used for validation?

ParseIntPipe
ValidationPipe
DefaultValuePipe
TransformPipe

Explanation: ValidationPipe validates request data.

Question 27: What is a guard used for?

Error handling
Authorization logic
Response mapping
Data validation

Explanation: Guards handle authorization logic.

Question 28: Which feature modifies responses before sending to client?

Pipes
Guards
Interceptors
Middleware

Explanation: Interceptors can modify responses.

Question 29: What is an exception filter used for?

Logging
Authentication
Handling errors
Validation

Explanation: Exception filters handle and format errors.

Question 30: Which decorator throws HTTP exceptions?

@Error()
@Exception()
HttpException class
@Throw()

Explanation: HttpException is used to throw HTTP errors.

Question 31: Which file manages project dependencies?

tsconfig.json
nest-cli.json
package.json
main.ts

Explanation: package.json manages dependencies.

Question 32: Which command starts the NestJS server in development?

nest run
npm start
nest serve
nest dev

Explanation: npm start runs the NestJS app.

Question 33: What is the default port for NestJS?

3000
4000
8080
5000

Explanation: NestJS runs on port 3000 by default.

Question 34: Which decorator injects a dependency?

@Provide()
@Use()
@Inject()
@Resolve()

Explanation: @Inject() explicitly injects dependencies.

Question 35: What does @UseGuards() do?

Apply middleware
Apply pipes
Apply guards to routes
Apply interceptors

Explanation: @UseGuards() applies guards.

Question 36: What does @UsePipes() do?

Applies validation pipes
Applies guards
Applies middleware
Applies filters

Explanation: @UsePipes() applies pipes.

Question 37: Which feature enables modular architecture?

Controllers
Modules
Services
Middleware

Explanation: Modules support modular architecture.

Question 38: Which NestJS feature supports REST APIs?

GraphQL only
Controllers and decorators
Templates
CLI

Explanation: Controllers and decorators define REST APIs.

Question 39: Which command generates a controller?

nest add controller
nest create controller
nest generate controller
nest new controller

Explanation: nest generate controller creates a controller.

Question 40: Which command generates a service?

nest new service
nest generate service
nest add service
nest create service

Explanation: nest generate service creates a service.

Question 41: Which configuration file controls NestJS CLI?

angular.json
vue.config.js
nest-cli.json
tsconfig.json

Explanation: nest-cli.json configures the CLI.

Question 42: What is the main benefit of NestJS?

Minimal setup
Strong structure and scalability
Frontend rendering
Database management

Explanation: NestJS provides a scalable backend architecture.

Question 43: Which NestJS feature promotes testability?

Decorators
Dependency Injection
Routing
Middleware

Explanation: Dependency injection improves testability.

Question 44: What is the ultimate goal of NestJS?

Frontend UI
Scalable server-side applications
Database optimization
Static websites

Explanation: NestJS is designed for scalable backend applications.

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NestJS Quiz ( Beginner )

Questions

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