Nestjs - Validating and Converting Query params [duplicate] - nestjs

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.