NestJS

What is NestJS?

A progressive Node.js framework for building efficient, reliable and scalable server-side applications.

1. Controllers:

Are responsible for handling inconming requests and returning responded to the client.

3. Guards:
Is a class annotated with the @Injectable() decorator.
Guards should implement the CanActivate interface.

2. Modules:

Is a class annotated with a @Module decorator.
Provides metadata that Nest makes user of to organize the application structure.

4. Middlewares:

Is a function which is called before the route handler.

5. Pipes:

Is a class annotated with the @Injectable() decorator.

6. Database:

Allowing you to easily integrate with any SQL or NoSQL database.

CLI

npm i -g @nest/cli

Use

nest new project-dominicode

platform agnostic

Websockets

The Building Blocks

It has all ..

TypeScript

RxJS

Angular

NestJS

Controller

export class CatController {
  constructor
     (private readonly catService: CatsService){}

  @ApiTags('cat')
  @Post('')
  async createCat(@Body() cat: CreateCatDto) {
    return this.catService.create(cat);
  }

Service

@Injectable()
export class CatsService {
  private readonly cats: Cat[] = [];

   create(cat: Cat) {
     this.cats.push(cat);
   }
  }

Module

@Module({
  controllers: [CatController],
  providers: [CatsService],
})
export class CatsModule  {
 
}

Bootstrap

async function bootstrap() {
  const opts: NestApplicationOptions = {};
  const app = await NestFactory.create
        <NestExpressApplication>(AppModule, opts);
  app.disable('x-powered-by');
  await app.listen(LISTEN_PORT);
}
bootstrap();

Adaptors

async function bootstrap() {
  const app = await 
        NestFactory.create<NestFastifyApplication>(
    AppModule,
    new FastifyAdapter()
  );
  await app.listen(3000);
}

Microservice

async function bootstrap() {
  const app = await 
   NestFactory.createMicroservice
    <MicroserviceOptions>(
    AppModule,
    {
      transport: Transport.TCP,
    },
  );
  await app.listen();
}