[Solved] Identify the error in this LocalStrategy validate method: async validate(username: string, password: string) { const user = this.authService.validateUser(username, password); if (!... | NestJS

NestJS - Authentication

Identify the error in this LocalStrategy validate method:

async validate(username: string, password: string) {
  const user = this.authService.validateUser(username, password);
  if (!user) {
    throw new UnauthorizedException();
  }
  return user;
}

AMissing await before authService.validateUser call

BUnauthorizedException should not be thrown

Cvalidate method should not be async

Dusername and password parameters are reversed

Step-by-Step Solution

Solution:

Step 1: Check async call usage
The method calls validateUser which returns a Promise, but lacks await.
Step 2: Understand consequences of missing await
Without await, user is a Promise, so if (!user) check is incorrect and login logic breaks.
Final Answer:
Missing await before authService.validateUser call -> Option A
Quick Check:
Async calls need await to get results [OK]

Quick Trick: Always await async calls in validate() [OK]

Common Mistakes:

Forgetting await on async service calls
Throwing exceptions incorrectly
Misordering parameters

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More NestJS Quizzes

Identify the error in this LocalStrategy validate method:

Step 1: Check async call usage

Step 2: Understand consequences of missing await

Final Answer:

Quick Check:

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