console.log("server running");
var serialPORT = 'COM10';             //  WINDOWS 10 VERSION
//var serialPORT = '/dev/ttyS0';      // LINUX SERVER
var serialport = require("serialport");
console.log("serialport module loaded");     // NEVER REACHES HERE
var port = new serialport(serialPORT, { baudRate:38400, }, (err)=>{
        if(err) console.log("Serialport Error, line #11", err.message);
        else console.log("\r\n\nserial port /dev/serial0 on pins #8: TXD, #10 RXD is open\r\n\n");
        return;
const Readline = serialport.parsers.Readline;
const parser = new Readline();
port.pipe(parser);
parser.on('data', onData);
//  REST OF SERVER ...

server running
internal/modules/cjs/loader.js:883
  throw err;
Error: Cannot find module 'serialport'
Require stack:
- C:\Users\Panos\Documents\node_js projects\server\index.js
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:880:15)
    at Function.Module._load (internal/modules/cjs/loader.js:725:27)
    at Module.require (internal/modules/cjs/loader.js:952:19)
    at require (internal/modules/cjs/helpers.js:88:18)
    at Object.<anonymous> (C:\Users\Panos\Documents\node_js projects\server\index.js:8:18)
    at Module._compile (internal/modules/cjs/loader.js:1063:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1092:10)
    at Module.load (internal/modules/cjs/loader.js:928:32)
    at Function.Module._load (internal/modules/cjs/loader.js:769:14)
    at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:72:12) {
  code: 'MODULE_NOT_FOUND',
  requireStack: [
    'C:\\Users\\Panos\\Documents\\node_js projects\\server\\index.js'
}

{
  "name": "server",
  "version": "1.0.0",
  "description": "node.js version of esp32 web server running on raspberry pi 4",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"