NestJs Questions

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Score: 🔥 117

Intermediate

Took 16 minutes

Programming Framework

NestJs

60%

Questions Attempted

10 / 10

Correct Answers

Incorrect Answers

Points Earned

🔥 6

Question 1

Which module is essential for implementing JWT authentication in a NestJS application?

@nestjs/jwt
@nestjs/passport
@nestjs/common
@nestjs/core

Explanation:

The @nestjs/jwt module provides the necessary utilities for signing, verifying, and handling JWTs in a NestJS application. This includes the JwtService for creating tokens and guards for protecting routes.

Question 2

How do you register a global exception filter in NestJS?

By using the @Catch() decorator on the global filter class.
By using the useGlobalFilters() method in the main.ts file.
By adding the global filter class to the providers array in the module definition.
By extending the base ExceptionFilter class and annotating it with the @Global() decorator.

Explanation:

You register a global exception filter using the useGlobalFilters() method provided by the NestJS application instance in your main.ts file. This ensures the filter is applied globally.

Question 3

Which testing type provides the most comprehensive coverage by simulating real user interactions with a running NestJS application?

Unit Testing
Integration Testing
End-to-End (E2E) Testing
Regression Testing

Explanation:

E2E tests act like real users, interacting with the application through the UI (if one exists) or API endpoints to validate the entire system's behavior.

Question 4

What is the correct way to apply multiple decorators to a single target in NestJS?

By chaining the decorator functions together using the . operator.
By placing the decorator names within square brackets [] above the target.
By using the @ApplyDecorators function provided by NestJS.
By passing multiple decorator functions as arguments to the target.

Explanation:

In TypeScript (and therefore NestJS), you apply multiple decorators by listing them within square brackets above the decorated element.

Question 5

What object in the intercept() method of a transformation interceptor allows you to modify the response stream?

context.switchToHttp().getResponse()
context.getRequest()
context.getNext()
context.switchToWs().getClient()

Explanation:

Within a transformation interceptor's intercept() method, you use context.switchToHttp().getResponse() to access and modify the response stream before it's sent back to the client.

Question 6

What is a common use case for a class decorator in NestJS?

Validating the structure of request payloads.
Modifying the response sent back to the client.
Adding common properties or methods to all instances of a class.
Defining custom route paths for controller methods.

Explanation:

Class decorators are well-suited for modifying the prototype of a class, effectively adding shared properties or methods to every object instantiated from that class.

Question 7

Why is it generally advisable to have a balance of different testing types (unit, integration, E2E) in a NestJS project?

To ensure comprehensive test coverage across different levels of the application
To minimize the execution time of the entire test suite
To reduce the need for manual testing efforts completely
To eliminate the possibility of introducing bugs during development entirely

Explanation:

A combination of testing types ensures that individual units, their interactions, and the overall system behavior are all thoroughly validated.

Question 8

What is a key advantage of using interceptors for cross-cutting concerns like logging and transformation in NestJS?

Improved code organization and separation of concerns
Reduced boilerplate code in controllers and services
Enhanced performance and reduced request latency
All of the above

Explanation:

Using interceptors in NestJS for tasks like logging, caching, and transformation brings multiple benefits, including improved code organization, reduced code duplication, and potentially enhanced performance due to their centralized nature.

Question 9

When should you use a global exception filter in NestJS?

To handle exceptions specific to a particular controller or route.
To implement custom error handling logic for a specific HTTP exception type.
To centralize error handling logic for exceptions thrown across your entire application.
To prevent any exceptions from being thrown in a production environment.

Explanation:

Global exception filters provide a centralized place to handle uncaught exceptions in your NestJS application. This promotes code reusability and a consistent error response format.

Question 10

What is a common approach to ensure data consistency when using CQRS and event-driven architecture in NestJS?

Using two-phase commit transactions for command and event handling
Implementing eventual consistency by updating read models asynchronously
Disabling caching mechanisms to guarantee real-time data consistency
Relying on the database's built-in transaction management system

Explanation:

Eventual consistency is a common strategy in CQRS, where changes are reflected in read models (used for queries) asynchronously after the command is processed and events are emitted.