NestJS Basics — Series 2

Preview — 3 of 10 questions

What is main.ts responsible for in a standard NestJS project?

javascript

import { NestFactory } from '@nestjs/core';
import { AppModule } from './app.module';

async function bootstrap() {
  const app = await NestFactory.create(AppModule);
  await app.listen(process.env.PORT ?? 3000);
}
bootstrap();

AIt declares the application's controllers and providers; AppModule only holds configuration values

BIt is the entry point: it builds the application instance from the root module and starts the HTTP server listening on a port

CIt is compiled into a service that Nest injects into every controller automatically

DIt runs once per incoming HTTP request, rebuilding the application for each one

What does this command do?

javascript

nest generate service users
# or, shorthand:
nest g s users

AIt creates users.service.ts plus a spec file, and registers the service in the nearest module's providers array

BIt only prints the file contents to the terminal so you can copy them manually

CIt creates a service and immediately deploys it as a standalone microservice

DIt rewrites every existing controller to inject the new service

What status codes do these two handlers return on success, by default?

javascript

@Controller('cats')
export class CatsController {
  @Get()
  findAll() { return []; }

  @Post()
  create() { return { id: 1 }; }
}

ABoth return 200 OK, because Nest applies one default status to every route

BBoth return 204 No Content unless a body is explicitly returned

CGET returns 200 OK and POST returns 201 Created

DNest returns 500 until you add an explicit @HttpCode() decorator

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