[Solved] Consider this guard implementation:async canActivate(context: ExecutionContext) { const user = await this.authService.validateUser(context);... }What will happen if validateUser returns null? | NestJS

NestJS - Guards

Consider this guard implementation:

async canActivate(context: ExecutionContext) {
  const user = await this.authService.validateUser(context);
  return user !== null;
}

What will happen if validateUser returns null?

AAccess is denied because canActivate returns false

BAccess is granted because null is truthy

CAn exception is thrown automatically

DThe guard retries validation

Step-by-Step Solution

Solution:

Step 1: Understand the return condition
canActivate returns true only if user is not null; null means false.
Step 2: Effect on access
Returning false denies access.
Final Answer:
Access is denied because canActivate returns false -> Option A
Quick Check:
Null user means false = D [OK]

Quick Trick: Null user means deny access [OK]

Common Mistakes:

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