Role-based guards in NestJS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to import the necessary decorator for roles.

NestJS

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

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AController

BUseGuards

CRoles

DSetMetadata

Attempts:

3 left

💡 Hint

Common Mistakes

Using Roles decorator which does not exist by default.

Confusing UseGuards with metadata setting.

The SetMetadata decorator is used to define custom metadata like roles in NestJS.

2fill in blank

medium

Complete the code to create a custom decorator named Roles.

NestJS

export const Roles = (...roles: string[]) => [1]('roles', roles);

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ASetMetadata

BUseGuards

CController

DInjectable

Attempts:

3 left

💡 Hint

Common Mistakes

Using UseGuards instead of SetMetadata.

Trying to use Injectable which is for services.

SetMetadata is used to create custom decorators that attach metadata like roles.

3fill in blank

hard

Fix the error in the guard method to get roles metadata.

NestJS

const roles = this.reflector.get<string[]>([1], context.getHandler());

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A'role'

B'roles'

C'permissions'

D'auth'

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'role' instead of 'roles' causes undefined metadata.

Using unrelated keys like 'permissions' or 'auth'.

The metadata key used for roles is 'roles', so it must match exactly.

4fill in blank

hard

Fill in the blank to check if user roles include any required role.

NestJS

if (!roles) return true; // Allow access if no roles are set

return user.roles.some(role => roles.[1](role)); // Check if user has any required role

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Aequals

Bexcludes

Cincludes

Dcontains

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'excludes' which is not a valid array method.

Returning false when no roles are set blocks access incorrectly.

The includes method checks if the user's role is in the required roles array. Returning true if no roles are set allows open access.

5fill in blank

hard

Fill all three blanks to apply the Roles guard to a controller method.

NestJS

@[1](RolesGuard)
@[2]('admin')
@[3]('dashboard')
async getDashboard() {
  return 'Admin Dashboard';
}

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AUseGuards

BRoles

CController

DGet

Attempts:

3 left

💡 Hint

Common Mistakes

Using Controller instead of Get for the route method.

Forgetting to apply UseGuards to activate the guard.

UseGuards applies the guard, Roles sets the required roles, and Get defines the route method.