[Solved] Identify the error in this custom pipe code:import { PipeTransform } from '@nestjs/common';export class MyPipe implements PipeTransform { transform(value) { return value.toUpperCase(); }} | NestJS

NestJS - Pipes

Identify the error in this custom pipe code:

import { PipeTransform } from '@nestjs/common';
export class MyPipe implements PipeTransform {
  transform(value) {
    return value.toUpperCase();
  }
}

AMissing type annotation for transform method parameter

BPipeTransform interface is not imported correctly

CClass should be decorated with @Injectable()

DtoUpperCase() cannot be called on all types of value

Step-by-Step Solution

Solution:

Step 1: Analyze transform method usage
Calling toUpperCase() assumes value is a string, but input can be any type.
Step 2: Identify the problem with calling toUpperCase()
If value is not a string, this will cause a runtime error.
Final Answer:
toUpperCase() cannot be called on all types of value -> Option D
Quick Check:
Ensure input type matches method calls [OK]

Quick Trick: Check input type before string methods [OK]

Common Mistakes:

Ignoring input type safety
Assuming all inputs are strings
Forgetting to decorate pipe with @Injectable() (optional)

Master "Pipes" in NestJS

9 interactive learning modes - each teaches the same concept differently

Learn Why Deep Visual Try Challenge Project Recall Perf

More NestJS Quizzes

Identify the error in this custom pipe code:

Step 1: Analyze transform method usage

Step 2: Identify the problem with calling toUpperCase()

Final Answer:

Quick Check:

Want More Practice?