tv-discover.js

const dgram = require('dgram');
const { Buffer } = require('buffer');

// const  = 'ssdp:all';
const SAMSUNG_TV_URN = 'urn:samsung.com:device:RemoteControlReceiver:1';
const PORT = 1900;
const TIMEOUT = 2000;

function broadcastSsdp(socket, target) {
    const query = Buffer.from(
        'M-SEARCH * HTTP/1.1\r\n' +
            `HOST: "239.255.255.250:${PORT}"\r\n` +
            'MAN: "ssdp:discover"\r\n' +
            'MX: 3\r\n' +
            `ST: ${target}\r\n\r\n`
    );

    socket.send(query, 0, query.length, PORT, '239.255.255.250');
}

function discover(urn) {
    const socket = dgram.createSocket('udp4');
    const devices = [];

    socket.on('listening', () => {
        broadcastSsdp(socket, urn);
    });

    socket.on('message', (chunk, info) => {
        const buffer = Buffer.from(chunk);
        const response = buffer.toString().trim().split('\r\n');

        response.forEach((item) => {
            const splitter = item.indexOf(':');

            if (splitter > -1) {
                const header = item.slice(0, splitter);
                const value = item
                    .slice(splitter, item.length)
                    .replace(': ', '');

                if (header === 'ST' && value === urn) {
                    devices.push({ target: urn, info });
                }
            }
        });
    });

    socket.bind(PORT, '0.0.0.0');

    return new Promise((resolve) => {
        setTimeout(() => {
            socket.close();
            resolve(devices);
        }, TIMEOUT);
    });
}

async function demo() {
    const devices = await discover(SAMSUNG_TV_URN);
    console.log(devices);
}

demo();