NestJS custom transform pipe with parameters and injected TypeOrm dataSource

I'm trying to write custom pipe for entity id validation. The idea is to accept entity class as parameter, get id from route and validate whether entity with such id exists.

So i have an endpoint:

@Post('track/:id')
addTrack(
  @Param('id', ParseUUIDPipe, new EntityIdValidationPipe(Track)) id: string,
) {
  return this.favsService.addTrack(id);
}

and here is custom pipe:

@Injectable()
export class EntityIdValidationPipe implements PipeTransform {
  constructor(private entityClass: EntityClassOrSchema) {}

  async transform(id: string, metadata: ArgumentMetadata): Promise<string> {
    // here i need to access TypeOrm's DataSource,
    // but i dont know how to inject it
    return id;
  }
}

As you can see above i'm using validation pipe with new keyword to pass an argument.
In transform method i want to do something like this:

this.dataSource.getRepository(this.entityClass).findOneBy({ id }) 

But i cant do it because i dont know how to inject TypeOrm DataSource object.

So basically my question is: How can i pass parameters to custom transform pipe and use DI in that pipe simultaneously?

Thank you.

Sounds like what you are actually wanting to do is create a mixin pipe, a function that will return a class reference so that Nest can still inject the datasource. It would look something like this:

export const EntityIdValidationPipe = (entityClass: EntityClassOrSchema) => {
  @Injectable()
  class EntityIdValidationMixinPipe {
    constructor(@InjectDataSourcec() private readonly dataSource: DataSource) {}
    async transform(id: string, metadata: ArgumentMetadata): Promise<string> {
      const entity = await this.dataSource.getRepository(entityClass).findOneBy({ id }) 
      // validate entity
      return id;
    }
  return EntityIdValidationMixinPipe;
}

For other references, check out Nest's AuthGuard() and FileInterceptor