how to creae a npm node code example

Example 1: create node project

#1. server.js
var express = require('express');
var app = express();

app.get('/', function (req, res) {
  res.status(200).send('Hello World!');
});

var port = process.env.PORT || 3000;

var server = app.listen(port, function() {
  console.log('Express server listening on port ' + port);
});

open cmd run server.js
"node server.js"
log:Express server listening on port 3000

& then

open link "http://localhost:3000/" in your browser and show result.

Example 2: how to create npm project

//Load HTTP module
const http = require("http");
const hostname = '127.0.0.1';
const port = 3000;

//Create HTTP server and listen on port 3000 for requests
const server = http.createServer((req, res) => {

  //Set the response HTTP header with HTTP status and Content type
  res.statusCode = 200;
  res.setHeader('Content-Type', 'text/plain');
  res.end('Hello World\n');
});

//listen for request on port 3000, and as a callback function have the port listened on logged
server.listen(port, hostname, () => {
  console.log(`Server running at http://${hostname}:${port}/`);
});