CODE EXAMPLE FOR TYPESCRIPT

nest js parseint pipe usage

import { PipeTransform, Injectable, ArgumentMetadata, BadRequestException } from '@nestjs/common';

@Injectable()
export class ParseIntPipe implements PipeTransform<string, number> {
  transform(value: string, metadata: ArgumentMetadata): number {
    const val = parseInt(value, 10);
    if (isNaN(val)) {
      throw new BadRequestException('Validation failed');
    }
    return val;
  }
}

// usage

@Get(':id')
async findOne(@Param('id', new ParseIntPipe()) id) {
  return this.catsService.findOne(id);
}

@Get(':id')
findOne(@Param('id', UserByIdPipe) userEntity: UserEntity) {
  return userEntity;
}