Understanding HTTP using Node.js "net" 1. Socket

1-socket.ts

import { createServer, Server, Socket } from 'net';

const port: number = 9903;

// ---------------------------------------------
// server
// ---------------------------------------------
const server: Server = createServer((connectedSocket: Socket) => { // 2. this is the client below
  console.log(`[server] connected client: ${JSON.stringify(connectedSocket.address())}`);
  
  connectedSocket.on('data', clientData => { // 4. receive data from client
    console.log(`[server] received data from client: ${clientData}`);
    
    connectedSocket.write(`~~echo~~ ${clientData.toString()}\r\n`); // 5. send data to client
  });
  
});

server.listen(port, () => {
  console.log(`[server] opened server: ${JSON.stringify(server.address())}`);
});

// ---------------------------------------------
// client
// ---------------------------------------------
const client: Socket = new Socket();

client.connect(port, '127.0.0.1', () => { // 1. connect to server
  console.log(`[client] connected`);
  client.write('hello world!'); // 3. send data to server
});

client.on('data', serverData => { // 6. receive data from server
  console.log(`[client] received data from server: ${serverData}`);
  client.destroy();
});

client.on('close', () => {
  console.log(`[client] connection closed`);
});