Built-in HTTP exceptions in NestJS - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ component_behavior

intermediate

What is the HTTP status code returned by NotFoundException in NestJS?

In NestJS, when you throw new NotFoundException(), what HTTP status code does the framework send back to the client?

A 404

B 403

C 500

D 200

💡 Hint

Think about what 'Not Found' means in HTTP status codes.

The NotFoundException in NestJS sends a 404 status code, which means the requested resource was not found.

📝 Syntax

intermediate

Which option correctly throws a BadRequestException with a custom message in NestJS?

You want to throw a BadRequestException with the message 'Invalid input data'. Which code snippet is correct?

A throw new BadRequestException(); 'Invalid input data';

B throw new BadRequestException('Invalid input data');

C throw BadRequestException('Invalid input data');

D BadRequestException('Invalid input data');

💡 Hint

Remember how to create and throw exceptions in JavaScript/TypeScript.

In NestJS, exceptions are classes. You must use new to create an instance and throw it.

❓ state_output

advanced

What is the response body when UnauthorizedException is thrown without a custom message?

In NestJS, if you throw new UnauthorizedException() without any message, what JSON response body will the client receive?

A {"statusCode":401,"message":"Unauthorized"}

B {"statusCode":401,"message":"Access denied"}

C {"statusCode":403,"message":"Unauthorized"}

D {"statusCode":400,"message":"Unauthorized"}

💡 Hint

Check the default message and status code for UnauthorizedException.

The default response body for UnauthorizedException includes statusCode 401 and message 'Unauthorized'.

🔧 Debug

advanced

Why does this NestJS code throw a runtime error?

Consider this code snippet in a controller method:

throw new HttpException('Forbidden', 403);

What is the cause of the runtime error?

A The second argument must be an object, not a number.

B The status code must be a string, not a number.

C The second argument must be an enum or HttpStatus constant, not a raw number.

D The second argument must be an HttpStatus enum value or number, but 403 is valid so no error.

💡 Hint

Check the NestJS HttpException constructor signature.

The HttpException constructor accepts a message and a status code number like 403. This code is valid and does not cause a runtime error.

🧠 Conceptual

expert

Which built-in NestJS HTTP exception class should you use to indicate a request is forbidden due to lack of permissions?

You want to respond with an HTTP status code that means the user is authenticated but not allowed to access the resource. Which NestJS exception class is the best choice?

A UnauthorizedException

B BadRequestException

C ForbiddenException

D NotFoundException

💡 Hint

Think about the difference between 401 and 403 HTTP status codes.

ForbiddenException corresponds to HTTP 403, meaning the user is authenticated but does not have permission.

UnauthorizedException means 401, the user is not authenticated.