how to start my server on node code example

Example 1: how to create node js server

/* ====== create node.js server with core 'http' module ====== */
// dependencies
const http = require("http");

// PORT
const PORT = 3000;

// server create
const server = http.createServer((req, res) => {
   if (req.url === "/") {
      res.write("This is home page.");
      res.end();
   } else if (req.url === "/about" && req.method === "GET") {
      res.write("This is about page.");
      res.end();
   } else {
      res.write("Not Found!");
      res.end();
   }
});

// server listen port
server.listen(PORT);

console.log(`Server is running on PORT: ${PORT}`);

/* ========== *** ========== */

/* ====== create node.js server with express.js framework ====== */
// dependencies
const express = require("express");

const app = express();

app.get("/", (req, res) => {
   res.send("This is home page.");
});

app.post("/", (req, res) => {
   res.send("This is home page with post request.");
});

// PORT
const PORT = 3000;

app.listen(PORT, () => {
   console.log(`Server is running on PORT: ${PORT}`);
});


// ======== Instructions ========
// save this as index.js
// you have to download and install node.js on your machine
// open terminal or command prompt
// type node index.js
// find your server at http://localhost:3000

Example 2: simple node server

// content of index.js
const http = require('http')
const port = 3000

const requestHandler = (request, response) => {
  console.log(request.url)
  response.end('Hello Node.js Server!')
}

const server = http.createServer(requestHandler)

server.listen(port, (err) => {
  if (err) {
    return console.log('something bad happened', err)
  }

  console.log(`server is listening on ${port}`)
})