Why guards control access in NestJS - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the Guard interface from NestJS.

NestJS

import { [1] } from '@nestjs/common';

Drag options to blanks, or click blank then click option'

ACanActivate

BController

CGuard

DModule

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'Guard' instead of 'CanActivate'.

Importing 'Controller' or 'Module' by mistake.

The CanActivate interface is used to create guards in NestJS.

2fill in blank

medium

Complete the code to implement the canActivate method in a guard.

NestJS

canActivate(context: ExecutionContext): [1] { return true; }

Drag options to blanks, or click blank then click option'

Astring

Bvoid

Cnumber

Dboolean

Attempts:

3 left

💡 Hint

Common Mistakes

Returning void or string instead of boolean.

Forgetting to return a value.

The canActivate method must return a boolean to allow or deny access.

3fill in blank

hard

Fix the error in the guard class declaration.

NestJS

export class AuthGuard implements [1] { }

Drag options to blanks, or click blank then click option'

AGuard

BInterceptor

CCanActivate

DPipeTransform

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'Guard' or 'Interceptor' instead of 'CanActivate'.

Confusing guards with pipes.

Guards must implement the CanActivate interface to control access.

4fill in blank

hard

Fill both blanks to create a guard that denies access when user is not authenticated.

NestJS

canActivate(context: ExecutionContext): [1] {
  const request = context.switchToHttp().getRequest();
  return request.user [2] undefined;
}

Drag options to blanks, or click blank then click option'

Aboolean

B!==

C===

Dvoid

Attempts:

3 left

💡 Hint

Common Mistakes

Returning void instead of boolean.

Using '===' instead of '!==' causing wrong access control.

The method returns a boolean. It denies access if request.user is not set.

5fill in blank

hard

Fill all three blanks to create a guard that allows access only if user role is 'admin'.

NestJS

canActivate(context: ExecutionContext): [1] {
  const request = context.switchToHttp().getRequest();
  const user = request.user;
  return user?.role [2] [3];
}

Drag options to blanks, or click blank then click option'

Aboolean

B===

C'admin'

D!==

Attempts:

3 left

💡 Hint

Common Mistakes

Using '!==' instead of '===' causing wrong access control.

Returning non-boolean values.

The guard returns a boolean. It checks if user.role is exactly 'admin' to allow access.