nestjs - How to change the type for query param?

Question

I want to transform my query param from string to number. I use dto technic.

import { IsOptional, IsInt, Min } from 'class-validator';
import { Transform } from 'class-transformer';

export class PaginationDto {
    @IsOptional()
    @IsInt()
    @Transform(val => Number.parseInt(val))
    @Min(1)
    perPage: number;

Use dto in controller

    @Get('/company')
    public async getCompanyNews(
        @Query() query: PaginationDto
    ) {
        console.log(typeof query.page);

Result: string.

How do I change the type correctly?

Answer 1

To ensure that DTOs get transformed, the transform: true option must be set for the ValidationPipe. Without that, the original incoming object will be passed after going through validations.