creating express server code example

Example 1: 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 2: expressjs server

// npm init
// npm i express

const express = require('express');
const server = express();

const PORT = 3000;

// Body parser
server.use(express.json());

// Homme page
server.get('/', (req, res) => {
  return res.send("<h1 style='text-align: center;'>Hello,<br />from the Express.js server!</h1>");
})

// About page
server.get('/about', (req, res) => {
  return res.send('<h2 style="text-align:center">About us</h2>');
})

// 404 page
server.use((req, res, next) =>{
  res.status(404);

  // respond with html page
  if (req.accepts('html')) {
    res.sendFile(__dirname + '/error404.html');
    return;
  }
  // respond with json
  else if (req.accepts('json')){
    res.send({
      status: 404,
      error: 'Not found'
    });
    return;
  }
  // respond with text
  else {
    res.type('txt').send('Error 404 - Not found');
  }
});

// Listening to the port
server.listen(PORT, () => {
  console.log(`Server is running on port ${PORT}`);
});

// Running the server: node server.js

Example 3: simple express server

const express = require('express');
const app = express();
const PORT = process.env.PORT || 3000;

app.get('/', (req, res) => {
  res.send('<h1>Some HTML</h1>');
  res.send('<p>Even more HTML</p>');
});

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

Example 4: 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 5: require express server.js

const express = require('express')const app = express() app.get('/', function (req, res) {  res.send('Hello World')}) app.listen(3000)

Example 6: create express server local

// create directory

//npm init -y
//npm i express --save

//create public directory
//create server.js

// <---- In the server js file --->

'use strict';

const express = require('express');
const app = express();
app.use(express.static('public'));// to connect with frontend html
app.use(express.json());//body parse

app.get('/', function(req,res){
	res.send('This is the Homepage');
  	//res.sendFile('index.html');
});

app.listen(3000);