Nestjs - Validating and Converting Query params [duplicate]

Question

I'm trying to validate the parameters that come in the query of a get request, but for some reason, the validation pipe is unable to identify the elements of the query.

import {
  Controller,
  Post,
  Query,
  Body,
  UseInterceptors,
  Param,
  Res,
  Logger,
} from '@nestjs/common';
import { Crud, CrudController, Override } from '@nestjsx/crud';

import { OpenScheduleDto } from './open-schedule.dto';
@Crud(Schedule)
export class ScheduleController
          implements CrudController<ScheduleService, Schedule> {
          constructor(public service: ScheduleService) {}

          get base(): CrudController<ScheduleService, Schedule> {
            return this;
          }

          @Override()
          async getMany(@Query() query: OpenScheduleDto) { 
             return query; 
         } 
    }

OpenSchedule.dto

import { IsNumber, IsOptional, IsString } from 'class-validator';
export class OpenScheduleDto {

  @IsNumber()
  companyId: number;

  @IsNumber()
  @IsOptional()
  professionalId: number;

  @IsString()
  @IsOptional()
  scheduleDate: string;
}

When I make a get request to http://localhost:3000/schedules?companyId=3&professionalId=1

I get unexpected errors:

{
    "statusCode": 400,
    "error": "Bad Request",
    "message": [
        {
            "target": {
                "companyId": "3",
                "professionalId": "1"
            },
            "value": "3",
            "property": "companyId",
            "children": [],
            "constraints": {
                "isNumber": "companyId must be a number"
            }
        },
        {
            "target": {
                "companyId": "3",
                "professionalId": "1"
            },
            "value": "1",
            "property": "professionalId",
            "children": [],
            "constraints": {
                "isNumber": "professionalId must be a number"
            }
        }
    ]
}

Answer 1

That is because when you use @Query parameters, everything is a string. It does not have number or boolean as data types like json. So you have to transform your value to a number first. For that, you can use class-transformer's @Transform:

import { IsNumber, IsOptional, IsString } from 'class-validator';
import { Transform } from 'class-transformer';
export class OpenScheduleDto {

  @Transform(id => parseInt(id))
  @IsNumber()
  companyId: number;

  @Transform(id => id ? parseInt(id) : id)
  @IsNumber()
  @IsOptional()
  professionalId?: number;

  @IsString()
  @IsOptional()
  scheduleDate?: string;
}

---

Note though, that this is unsafe because e.g. parseInt('5abc010') is 5. So you might want to do additional checks in your transformation function.

Answer 2

You could also try setting enableImplicitConversion as true in your ValidationPipe.

app.useGlobalPipes(new ValidationPipe({
  transform: true,
  transformOptions: {
    enableImplicitConversion: true, // <- This line here
  },
}));

This should work locally e.g., in a Controller or method as well.