Guard interface (canActivate) in NestJS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

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

NestJS

canActivate(context: ExecutionContext): boolean | Promise<boolean> | Observable<boolean> {
  return [1];
}

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

Atrue

Bfalse

Cnull

Dundefined

Attempts:

3 left

💡 Hint

Common Mistakes

Returning false blocks access.

Returning null or undefined causes errors.

The canActivate method must return true to allow access.

2fill in blank

medium

Complete the code to extract the request object inside canActivate using ExecutionContext.

NestJS

const request = context.switchToHttp().[1]();

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

AgetResponse

BgetNext

CgetRequest

DgetHandler

Attempts:

3 left

💡 Hint

Common Mistakes

Using getResponse instead of getRequest.

Trying to access request directly without switchToHttp.

Use getRequest() to access the HTTP request object inside the guard.

3fill in blank

hard

Fix the error in the guard method to correctly check if user is authenticated.

NestJS

const user = request.user;
if (!user) {
  throw new [1]('Unauthorized');
}
return true;

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

AForbiddenException

BUnauthorizedException

CBadRequestException

DNotFoundException

Attempts:

3 left

💡 Hint

Common Mistakes

Throwing ForbiddenException instead of UnauthorizedException.

Not throwing any exception and returning false.

Throw UnauthorizedException when the user is not authenticated.

4fill in blank

hard

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

NestJS

const user = request.user;
return user?.role [1] [2];

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

A===

B!==

C'admin'

D'user'

Attempts:

3 left

💡 Hint

Common Mistakes

Using !== instead of ===.

Comparing to 'user' instead of 'admin'.

The guard returns true only if user.role === 'admin'.

5fill in blank

hard

Fill all three blanks to implement a guard that checks if request method is POST and user is authenticated.

NestJS

const request = context.switchToHttp().getRequest();
if (request.method [1] 'POST' && request.user [2] null) {
  return [3];
}
return false;

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

A===

B!==

Ctrue

Dfalse

Attempts:

3 left

💡 Hint

Common Mistakes

Using == instead of ===.

Checking user === null instead of !== null.

Returning false instead of true when conditions met.

The guard checks if method is 'POST' and user is not null, then returns true to allow access.