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In NestJS, what is the primary function of the DefaultValuePipe when used in a controller parameter?

easy📝 Conceptual Q1 of 15
NestJS - Pipes
In NestJS, what is the primary function of the DefaultValuePipe when used in a controller parameter?
AIt transforms the parameter value to uppercase.
BIt validates that the parameter is of a specific type.
CIt assigns a default value to a parameter if the incoming request does not provide one.
DIt logs the parameter value for debugging purposes.
Step-by-Step Solution
Solution:

  1. Step 1: Understand DefaultValuePipe's role

    The DefaultValuePipe is designed to provide a fallback value when a parameter is missing or undefined in the request.

  2. Step 2: Differentiate from other pipes

    Unlike validation or transformation pipes, DefaultValuePipe only sets a default value and does not modify or validate the input.

  3. Final Answer:

    It assigns a default value to a parameter if the incoming request does not provide one. -> Option C

  4. Quick Check:

    DefaultValuePipe sets fallback values [OK]
Quick Trick: DefaultValuePipe sets fallback values if missing [OK]
Common Mistakes:
  • Confusing DefaultValuePipe with validation pipes
  • Assuming it transforms or validates input
  • Thinking it applies when parameter is null

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