Does the NestJS framework support working with the TCP protocol?

Yes, the NestJS framework supports working with the TCP protocol. It provides a built-in mechanism for creating TCP servers and clients through the microservices module.

Example of creating a TCP server in NestJS:

import { Controller } from '@nestjs/common';
import { MessagePattern } from '@nestjs/microservices';

@Controller()
export class AppController {
  @MessagePattern({ cmd: 'sum' })
  accumulate(data: number[]): number {
    return (data || []).reduce((a, b) => a + b, 0);
  }
}

And running a microservice with TCP transport:

import { NestFactory } from '@nestjs/core';
import { MicroserviceOptions, Transport } from '@nestjs/microservices';
import { AppModule } from './app.module';

async function bootstrap() {
  const app = await NestFactory.createMicroservice<MicroserviceOptions>(AppModule, {
    transport: Transport.TCP,
    options: { host: '127.0.0.1', port: 3001 },
  });
  await app.listen();
}
bootstrap();

Thus, NestJS makes it easy to create TCP services for microservice architecture.