What is the recommended approach to unit test a custom Guard in NestJS?
By relying solely on console logs within the Guard's code to verify its behavior.
By manually triggering API requests using tools like Postman and observing the responses.
By setting up a complete end-to-end testing environment that interacts with real databases and services.
By mocking external dependencies like database calls or HTTP requests, focusing on testing the Guard's logic in isolation.
Integration testing in NestJS primarily aims to verify what aspect of the application?
The application's behavior in a real browser environment
The interaction between different modules and components
The security vulnerabilities within the codebase
The correctness of individual functions or methods
When might you choose to use a custom decorator instead of middleware in NestJS?
When you need to perform asynchronous operations before or after a request.
When you want to modify the routing behavior of your application.
When the logic you want to apply is highly specific to a single method or parameter.
When you need access to the request or response objects within the logic.
In TypeORM, what is the purpose of an Entity?
To define routes in a NestJS application
To handle HTTP requests
To manage database connections
To define database tables and their columns
How do you activate a custom Guard globally in a NestJS application?
By manually adding the guard to each route handler where it's needed.
By using the @Global() decorator before the guard class definition.
@Global()
By registering the guard in the providers array of the module where it's defined.
providers
By defining the guard within the main.ts file of your application.
main.ts
What is the difference between HttpException and a custom exception class in NestJS?
HttpException
HttpException is deprecated and should always be replaced with custom exception classes.
There is no practical difference; both can be used interchangeably for error handling.
HttpException is used for generic HTTP errors, while custom exceptions represent specific business logic errors.
HttpException must be caught by custom exception filters, while custom exceptions are handled automatically.
How does NestJS support the implementation of query handlers in a CQRS system?
Through dedicated decorators for defining query handlers
By providing built-in classes for handling database queries
Query handlers are not directly supported, they are typically implemented as service methods
By integrating with GraphQL for efficient query resolution
What is the primary function of a Pipe in NestJS?
To manage dependency injection within the application.
To transform input data into the desired format.
To define middleware for routing HTTP requests.
To handle database queries and operations.
What is the role of a 'Guard' in the context of NestJS authentication?
Defining API routes
Storing user credentials
Encrypting sensitive data
Validating incoming requests and verifying user authentication
What is the primary purpose of a Guard in NestJS?
To define the structure of a request body.
To handle database interactions.
To render HTML templates on the server.
To control access to routes or resources based on certain conditions.