(Node.js) Socket Send/Receive 16-bit Integers

Demonstrates sending and receiving 16-bit integers over a socket connection using either big-endian or little-endian byte ordering.

Install Chilkat for Node.js and Electron using npm at Chilkat npm packages for Node.js Chilkat npm packages for Electron on Windows, Linux, MacOSX, and ARM

var os = require('os');
if (os.platform() == 'win32') {  
    if (os.arch() == 'ia32') {
        var chilkat = require('@chilkat/ck-node21-win-ia32');
    } else {
        var chilkat = require('@chilkat/ck-node21-win64'); 
    }
} else if (os.platform() == 'linux') {
    if (os.arch() == 'arm') {
        var chilkat = require('@chilkat/ck-node21-arm');
    } else if (os.arch() == 'x86') {
        var chilkat = require('@chilkat/ck-node21-linux32');
    } else {
        var chilkat = require('@chilkat/ck-node21-linux64');
    }
} else if (os.platform() == 'darwin') {
    if (os.arch() == 'arm64') {
        var chilkat = require('@chilkat/ck-node21-mac-m1');
    } else {
        var chilkat = require('@chilkat/ck-node21-macosx');
    }
}

function chilkatExample() {

    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    var sock = new chilkat.Socket();

    // --------------------------------------------------------------------
    // This example uses the public TCP echo service at https://tcpbin.com/
    // --------------------------------------------------------------------

    var useTls = false;
    var port = 4242;
    var maxWaitMs = 5000;
    var success = sock.Connect("tcpbin.com",port,useTls,maxWaitMs);
    if (success == false) {
        console.log(sock.LastErrorText);
        return;
    }

    // Wait a max of 2 seconds for a response..
    sock.MaxReadIdleMs = 2000;

    // Send a 16-bit integer using big-endian byte ordering (also called network byte order)
    // 12022 decimal = 2EF6 hex
    var value = 12022;
    var bigEndian = true;
    sock.SendInt16(value,bigEndian);
    // Send it again, because we'll read it two different ways..
    sock.SendInt16(value,bigEndian);

    // The tcpbin.com echo server only echoes after receiving an LF (linefeed char)
    sock.SendByte(10);

    // Let's see hex values of the 2 bytes sent in network byte order (big-endian)
    // (The echo server sends back exactly the bytes received.)
    var hexStr = sock.ReceiveNBytesENC(2,"hex");

    // In the big-ending byte order, the byte order is most significant byte to least significant,
    // therefore we should see the bytes in the order 0x2E 0xF6.
    console.log("Expecting big-endian 2EF6");
    console.log(hexStr);

    // Let's read directly to an integer..
    success = sock.ReceiveInt16(bigEndian,true);
    console.log("Expecting 12022");
    console.log("Received: " + sock.ReceivedInt);

    // Consume the LF that gets echoed back..
    sock.ReceiveByte(true);

    // --------------------------------------------------------------------
    // Let's do the same thing, but with little-endian byte ordering.

    console.log("----");

    // 12022 decimal = 2EF6 hex, but little-endian byte ordering will send the bytes in the order 0xF6 0x2E
    value = 12022;
    bigEndian = false;
    sock.SendInt16(value,bigEndian);
    sock.SendInt16(value,bigEndian);
    sock.SendByte(10);

    hexStr = sock.ReceiveNBytesENC(2,"hex");

    console.log("Expecting little-endian F62E");
    console.log(hexStr);

    success = sock.ReceiveInt16(bigEndian,true);
    console.log("Expecting 12022");
    console.log("Received: " + sock.ReceivedInt);

    // Consume the LF that gets echoed back..
    sock.ReceiveByte(true);

    sock.Close(1000);

    // Output:

    // Expecting big-endian 2EF6
    // 2EF6
    // Expecting 12022
    // Received: 12022
    // ----
    // Expecting little-endian F62E
    // F62E
    // Expecting 12022
    // Received: 12022

}

chilkatExample();