Node UDP echo server (use "netcat -u localhost 8080" for client)

udp-server-echo.js

const
  dgram  = require("dgram"),
  server = dgram.createSocket("udp4");

const
  PORT = 8080,
  HOST = "0.0.0.0";

server.on("listening", () => {
  var address = server.address();
  console.log(`Started UDP server on ${address.address}:${address.port}`);
});

server.on("message", (message, rinfo) => {
  message = message.toString(); // get string from buffer
  if (message.slice(-1) == "\n")
    message = message.slice(0, -1);
  console.log(`${rinfo.address}:${rinfo.port} - ${message}`);

  server.send(`echo: ${message}\n`, rinfo.port, rinfo.address, (err) => {
    if (err)
      console.error(err);
  });
});

server.bind(PORT, HOST);