Bird
0
0

Why does ValidationPipe ignore properties without validation decorators in a DTO when whitelist: true is enabled?

hard📝 Conceptual Q10 of 15
NestJS - Pipes
Why does ValidationPipe ignore properties without validation decorators in a DTO when whitelist: true is enabled?
ABecause NestJS ignores DTO properties without decorators automatically
BBecause ValidationPipe only validates primitive types by default
CBecause transform option disables validation for undecorated properties
DBecause whitelist removes all properties not explicitly validated by decorators
Step-by-Step Solution
Solution:

  1. Step 1: Understand whitelist behavior

    Whitelist removes any properties not explicitly allowed by validation decorators in the DTO.

  2. Step 2: Connect to decorator presence

    Properties without decorators are considered unknown and removed when whitelist is true.

  3. Final Answer:

    Because whitelist removes all properties not explicitly validated by decorators -> Option D

  4. Quick Check:

    Whitelist true removes undecorated properties [OK]
Quick Trick: Whitelist true keeps only decorated properties [OK]
Common Mistakes:
  • Thinking transform disables validation
  • Assuming NestJS ignores undecorated properties by default
  • Confusing whitelist with type conversion

Want More Practice?

15+ quiz questions · All difficulty levels · Free

Free Signup - Practice All Questions
More NestJS Quizzes
Authentication - Role-based authorization - Quiz 4medium Database with Prisma - Relations in Prisma - Quiz 10hard Database with TypeORM - Relations (OneToMany, ManyToOne, ManyToMany) - Quiz 8hard Guards - Why guards control access - Quiz 2easy Guards - JWT authentication guard - Quiz 12easy Guards - Guard binding levels - Quiz 6medium Interceptors - Exception mapping interceptor - Quiz 14medium Interceptors - Response transformation - Quiz 9hard Middleware - Global middleware - Quiz 13medium Pipes - Built-in pipes (ParseIntPipe, ParseBoolPipe) - Quiz 5medium