Solution:Step 1: Understand transform option effectWith transform: true, ValidationPipe converts input types to match DTO properties.Step 2: Apply to input dataThe string "30" is converted to number 30, which satisfies the @IsInt() validation.Final Answer:The string "30" is converted to number 30 an

[Solved] Given this DTO:class UserDto { @IsInt() age: number;}And ValidationPipe with transform: true, what happens when the input is { "age": "30" }? | NestJS

NestJS - Pipes

Given this DTO:

class UserDto {  @IsInt()  age: number;}

And ValidationPipe with transform: true, what happens when the input is { "age": "30" }?

AThe string "30" is converted to number 30 and passes validation

BValidation fails because age is a string, not a number

CValidationPipe throws a runtime error

DThe input is accepted as string without conversion

Step-by-Step Solution

Solution:

Step 1: Understand transform option effect
With transform: true, ValidationPipe converts input types to match DTO properties.
Step 2: Apply to input data
The string "30" is converted to number 30, which satisfies the @IsInt() validation.
Final Answer:
The string "30" is converted to number 30 and passes validation -> Option A
Quick Check:
transform: true converts strings to numbers [OK]

Quick Trick: transform: true converts input types automatically [OK]

Common Mistakes:

Assuming string input always fails validation
Expecting runtime errors on type mismatch
Ignoring transform option effect

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Given this DTO:

Step 1: Understand transform option effect

Step 2: Apply to input data

Final Answer:

Quick Check:

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