NestJs Questions

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Score: 🔥 117

Beginner

Took 7 minutes

Programming Framework

NestJs

100%

Questions Attempted

10 / 10

Correct Answers

Incorrect Answers

Points Earned

🔥 10

Question 1

What is the difference between a provider and a service in NestJS?

Providers are used for database operations, while services handle business logic.
Providers and services are essentially the same thing, with no real distinction.
Providers are decorated with @Injectable(), while services are decorated with @Service().
Providers are classes that can be injected as dependencies, while a service is a specific type of provider with business logic.

Explanation:

While all services are providers in NestJS, not all providers are services. Services are specifically meant to encapsulate business logic, making them a specialized form of a provider.

Question 2

What is the role of the 'main.ts' file in a NestJS project?

Defines the application's database schema and models
Contains unit tests for the application's logic
Creates and configures the NestJS application instance
Stores environment variables and configuration settings

Explanation:

The main.ts file is the entry point of your NestJS application. It bootstraps the NestJS application, often setting up the listening port and other core configurations.

Question 3

What is the purpose of Providers in NestJS?

To define database models and interact with the database
To handle routing and HTTP requests
To provide reusable logic and services that can be injected into other components
To render the user interface and manage view templates

Explanation:

Providers are a key concept in NestJS for building reusable and modular code. They represent services, repositories, or any other logic that can be shared across your application.

Question 4

Which decorator is used to apply middleware to a specific route in NestJS?

@UseMiddleware()
@Middleware()
@Route()
@ApplyMiddleware()

Explanation:

The @UseMiddleware() decorator is used to bind middleware to specific routes or controllers. You can apply it at the method level for individual routes or at the controller level to affect all routes within that controller.

Question 5

What is the recommended way to access query parameters in a NestJS controller?

Using req.query
Using the @Query() decorator
Accessing params.query
Through the context.request object

Explanation:

The @Query() decorator provides a clean and type-safe way to access query parameters from the request object. It allows retrieving specific parameters or the entire query object.

Question 6

What is the role of the 'HttpException' class in NestJS exception handling?

It's a base class for creating custom exceptions with HTTP status codes.
It's a decorator for marking methods that handle HTTP exceptions.
It's a module for configuring global exception handling.
It's an interface for defining the structure of exception objects.

Explanation:

The HttpException class provides a convenient way to create custom exceptions that carry appropriate HTTP status codes, making it easy to send meaningful error responses to clients.

Question 7

How can you access the currently logged-in user within your middleware in NestJS?

By injecting the Request object into the middleware function.
By using the user property of the Response object.
By accessing the req.user object, assuming you have an authentication middleware set up.
By querying the database directly within the middleware.

Explanation:

If you're using an authentication middleware in NestJS, it typically attaches the authenticated user object to the request object. You can access this user information within your middleware by referring to req.user.

Question 8

How would you define a route parameter named 'id' in a NestJS route path?

/users/:id
/users/{id}
/users?id=value
/users/<id>

Explanation:

In NestJS, route parameters are defined using the colon (:) followed by the parameter name. This pattern captures the value from the URL and makes it accessible within the route handler.

Question 9

What is the primary programming language used for developing NestJS applications?

JavaScript
Python
Java
C#

Explanation:

NestJS is built on top of Node.js, which uses JavaScript as its primary programming language. While TypeScript is often preferred, you can write NestJS applications directly in JavaScript.

Question 10

What is NOT a benefit of using Dependency Injection in NestJS?

Improved code testability.
Increased code coupling.
Enhanced code reusability.
Better maintainability of code.

Explanation:

Dependency Injection promotes loose coupling, not increased coupling. It allows components to depend on abstractions (interfaces) rather than concrete implementations.