How to make class-validator to stop on error?

Question

I want class validator to stop validation as soon as the first error is found.

I know there is a stopAtFirstError option, but that prevents further validation on property level only. I want to stop it globally:

@IsString() // Let's say this received invalid value
someStr: string

@IsInt() // I want this to be NOT executed
someNuber: number

Is this possible?

Answer 1

Since there is no official support for this, I implemented a hacky way to make it work. Although it doesn't stop the validation, only returns the message from initial one & ignores the rest.

ValidationErrorException

// validation-error.exception.ts

import { HttpException, HttpStatus } from "@nestjs/common";

export class ValidationErrorException extends HttpException {
  data: any;
  constructor(data: any) {
    super('ValidationError', HttpStatus.BAD_REQUEST);
    this.data = data
  }
  getData(){
    return this.data;
  }
}

Use Exception Factory to return the exception

// main.ts

app.useGlobalPipes(
    new ValidationPipe({
      whitelist: true,
      forbidNonWhitelisted: true,
      stopAtFirstError: true,
      exceptionFactory: (errors: ValidationError[]) => {
        return new ValidationErrorException(errors);
      },
    }),
  );

Validation Error Filter

// validation-error.filter.ts

import { ExceptionFilter, Catch, ArgumentsHost } from '@nestjs/common';
import { Response } from 'express';
import { ValidationErrorException } from './validation-error.exception';

@Catch(ValidationErrorException)
export class ValidationErrorFilter implements ExceptionFilter {
  catch(exception: ValidationErrorException, host: ArgumentsHost) {
    const response = host.switchToHttp().getResponse<Response>();
    const status = exception.getStatus();
    let constraints = exception.getData()[0].constraints

    response
      .status(status)
      .json({
        statusCode: status,
        message: constraints[Object.keys(constraints)[0]],
        error: exception.message
      });
  }
}

Use The filter

// app.module.ts

providers: [
    {
      provide: APP_FILTER,
      useClass: ValidationErrorFilter,
    },
  ],