networks

echoClient.js

const net = require('net');
const readline = require('readline');

const client = net.connect({port: 8124}, function () {
  console.log('client connected');
});

client.on('end', function () {
  console.log('client disconnected');
});

client.on('data', function (data) {
  console.log(data.toString());
});

client.on('error', function(err) {
  console.log(err);
  process.exit(-1);
})

// readline
const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout,
  prompt: '> '
});

// enter interactive 
rl.prompt();
rl.on('line', (line) => {
  client.write(line);
  rl.prompt();
}).on('close', () => {
  console.log('Have a great day!');
  client.end();
});

echoServer.js

var net = require('net');
var log = console.log;

var server = net.createServer(function (socket) {
  // new connection
  socket.on('data', function (data) {
    const info = data.toString();
    socket.write(info);
    log(`received: ${info}`);
  });

  socket.on('end', function () {
    log('client disconnected');
  });

  socket.write('hello\r\n');
});

server.on('error', function (err) {
  throw err;
});

server.listen(8124, function () {
  log('server bound, 8124')
});