udp-broadcast

client.js

// Require node js dgram module.
var dgram = require('dgram');

// Create a udp socket client object.
var client = dgram.createSocket("udp4");

// message variable is used to save user input text.
var message = "";

// Set command line input character encoding to utf-8.
process.stdin.setEncoding('utf-8');

// When receive user input data in console.
process.stdin.on('data', function (message) {
    // If user do not input data in command line then send default message.
    if (message == null || message.length == 0) {
        message = "Hello udp server.";
    }
    // console.log("User input : " + message);
    // Create a node Buffer object to wrap message object.
    message = Buffer.from(message, 'utf-8');
    // Send message to udp server through client socket.
    client.send(message, 0, message.length, 8089, "192.168.137.255");
});

server.js

// Require dgram module.
var dgram = require('dgram');

// Create udp server socket object.
var server = dgram.createSocket("udp4");

// Make udp server listen on port 8089.
server.bind(8089);

// When udp server receive message.
server.on("message", function (message) {
    // Create output message.
    var output = "Udp server receive message : " + message + "\n";
    // Print received message in stdout, here is log console.
    process.stdout.write(output);
});

// When udp server started and listening.
server.on('listening', function () {
    // Get and print udp server listening ip address and port number in log console. 
    var address = server.address(); 
    console.log('UDP Server started and listening on ' + address.address + ":" + address.port);
});