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NAuthValidationPipe

Package: @nauth-toolkit/nestjs Type: NestJS Pipe

import { NAuthValidationPipe } from '@nauth-toolkit/nestjs';

Overview​

NAuthValidationPipe is a drop-in replacement for NestJS's built-in ValidationPipe that ensures validation failures always serialize as NAuthException in the NAUTHError format, rather than NestJS's BadRequestException with a different payload shape.

Why this exists:

  • Nest's ValidationPipe throws BadRequestException with message as an array.
  • NAuthValidationPipe keeps message as a string and places field errors under details.validationErrors.
  • This keeps the error contract consistent across all nauth-toolkit endpoints.

Usage​

Register globally in main.ts alongside NAuthHttpExceptionFilter:

import { NestFactory } from '@nestjs/core';
import { AppModule } from './app.module';
import { NAuthValidationPipe, NAuthHttpExceptionFilter } from '@nauth-toolkit/nestjs';

async function bootstrap() {
  const app = await NestFactory.create(AppModule);
  app.useGlobalPipes(new NAuthValidationPipe());
  app.useGlobalFilters(new NAuthHttpExceptionFilter());
  await app.listen(3000);
}
bootstrap();
tip

Use NAuthValidationPipe together with NAuthHttpExceptionFilter to ensure a consistent error response format across all endpoints.

Behavior​

InputBehavior
Valid DTOReturns the validated and transformed DTO instance
Invalid DTO (validation errors)Throws NAuthException with field errors in details.validationErrors
Primitive type (string, number)Passes through without validation
undefined valuePasses through without validation (GET requests, optional bodies)

Error Response Shape​

When validation fails, the response follows the standard NAuthException format:

{
  "statusCode": 400,
  "message": "Validation failed",
  "errorCode": "VALIDATION_ERROR",
  "details": {
    "validationErrors": {
      "email": ["Invalid email format"],
      "password": ["Password must be at least 8 characters"]
    }
  }
}
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