Handling HTTP Errors inside services - nestjs

Question

I'm learning Nest, but there is a practice that i don't really like even in the official tutorial. It's one of Handling HTTP specific errors inside services. If later, for some services i'll used a protocol other that HTTP that will use a Service that handle specific HTTP errors, it don't think it's a best practice. As I'm not yet a Nestjs expert, here is how i'm trying to handle this situation:
// errors.interface.ts
export interface IError {
errorCode: number;
errorMessage: string;
}
import { Injectable } from '#nestjs/common';
import { IError } from './errors.interface';
#Injectable()
export class UserService {
// ...
async remove(id: number): Promise<Partial<User> | IError> {
const user = await this.userRepository.findOne({ where: { id } });
if (!user) {
return { errorCode: 404, errorMessage: 'user not found' };
}
await this.userRepository.remove(user);
return {
id,
};
}
}```
Here is my controller.
```// user.controller.ts
import { Controller, Get, HttpException, HttpStatus } from '#nestjs/common';
import { UserService } from './user.service';
import { IError } from './errors.interface';
#Controller('users')
export class UserController {
constructor(private userService: UserService) {}
#Get(':id')
async remove(#Param('id') id: number) {
const result = await this.userService.remove(id);
if ('errorCode' in result) {
throw new HttpException(result.errorMessage, result.errorCode);
}
return result;
}
}
As you can see, I'm trying to handle HTTP-specific errors inside HTTP controllers.
I don't have enough experience with Nestjs, maybe there are better ways to tackle these kinds of problems. I would like to know what is the best practice.

Answer 1

To create a Nest application instance, we use the core NestFactory class. NestFactory exposes a few static methods that allow creating an application instance. The create() method returns an application object, which fulfills the INestApplication interface. This object provides a set of methods which are described in the coming chapters. In the main.ts example above, we simply start up our HTTP listener, which lets the application await inbound HTTP requests.
so you can only work with HTTP requests and handling HTTP specific errors inside services is in fact the best practice.