Is it possible to validate single route parameter?

Question

Let's say I have following route:

companies/{companyId}/departments/{departmentId}/employees

Is it possible to validate both resources ids (companyId, departmentId) separately? I've tried following but it's not working.

class ResourceId {
  @IsNumberString()
  @StringNumberRange(...) // my custom validator
  id: number;
}

@Get(':companyId/departments/:departmentId/employees')
getEmployees(
  @Param('companyId') companyId: ResourceId,
  @Param('departmentId') departmentId: ResourceId,
) {}

I have multiple cases when there is more than one parameter in the single route. I would not like to create separate validation class for every route. Is there a way to handle this problem in a different way?

Answer 1

As of 2022, NestJS docs say that it's possible to validate route params using the built-in validation pipe.

In a controller:

@Get(':id')
findOne(@Param() params: FindOneParams) {
  return 'This action returns a user';
}

Validation class:

import { IsNumberString } from 'class-validator';

export class FindOneParams {
  @IsNumberString()
  id: number;
}

Ref: https://docs.nestjs.com/techniques/validation#auto-validation