node.js express server example

Example 1: express.js server

/* ====== 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: 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: express js 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: node js express

// node js -> express -> basic example: static folder, 404 page

const express = require('express');
const path = require('path');
const PORT = process.env.PORT || 5000;

const app = express();

function error404(req, res) {
  res.status(404);

  if (req.accepts('html')) {
    res.sendFile(path.join(__dirname, 'public/errors/404.html'));
    return;
  }

  if (req.accepts('json')) {
    res.send({
      status: 404,
      error: 'Not found'
    });
    return;
  }
  
  res.type('txt').send('404 - Not found');
}

app
  .use(express.static(path.join(__dirname, 'public')))
  .use(error404)
  .listen(PORT, () => console.log(`Listening on ${ 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)