reconnect-tcp-client.js

const net = require('net');
const clientTcp = net.Socket();
let intervalTcpConnect = false;
var isTcpConnected = false;

function connectTcp() {
    clientTcp.connect({
        host: 'localhost',
        port: 5060,
    });
}

function launchTcpIntervalConnect() {
    if (intervalTcpConnect != false) return;

    isTcpConnected = false;
    intervalTcpConnect = setInterval(connectTcp, 3 * 1000);
}

function clearTcpIntervalConnect() {
    if (intervalTcpConnect == false) return;
    clearInterval(intervalTcpConnect);
    intervalTcpConnect = false;
}

clientTcp.on('connect', () => {
    isTcpConnected = true;
    clearTcpIntervalConnect();
    console.log('connected to %s:%s', 'localhost', 5060);
    clientTcp.write('client connected');
});

clientTcp.on('error', (err) => {
    console.error(err.message);
    launchTcpIntervalConnect();
});

clientTcp.on('close', launchTcpIntervalConnect);
clientTcp.on('end', launchTcpIntervalConnect);

connectTcp();

function sendTcpMessageTest(msg) {
    if (isTcpConnected) clientTcp.write(msg);
}

setInterval(() => {
    sendTcpMessageTest('sendTcpMessageTest()');
}, 3 * 1000);