basic node app code example

Example 1: nodejs hello world

const http = require('http');

const hostname = '127.0.0.1';
const port = 3000;

const server = http.createServer((req, res) => {
  res.statusCode = 200;
  res.setHeader('Content-Type', 'text/plain');
  res.end('Hello World');
});

server.listen(port, hostname, () => {
  console.log(`Server running at http://${hostname}:${port}/`);
});

Example 2: express hello world

//to run : node filename.js
const express = require('express')
const app = express()
const port = 3000

app.get('/', (req, res) => res.send('Hello World!'))

app.listen(port, () => console.log(`Example app listening at http://localhost:${port}`))

//visit localhost:3000
// assuming you have done 1) npm init 2) npm install express

Example 3: sample express app

const express = require('express')
const app = express()
const port = 3000

app.get('/', (req, res) => res.send('Hello World!'))

app.listen(port, () => console.log(`Example app listening at http://localhost:${port}`))

Example 4: 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 5: node app create

using command line >>> 

npm init

open text editor create a js file. for example like index.js and paste following code.

>>> 
  
const http = require('http');

const hostname = '127.0.0.1';
const port = 3000;

const server = http.createServer((req, res) => {
  res.statusCode = 200;
  res.setHeader('Content-Type', 'text/plain');
  res.end('Hello World');
});

server.listen(port, hostname, () => {
  console.log(`Server running at http://${hostname}:${port}/`);
});

----

run using 
node app.js