how to create server in node js using express

                                    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}`));

                                    You can run the application generator with the npx command (available in Node.js 8.2.0).
$ npx express-generator
For earlier Node versions, install the application generator as a global npm package and then launch it:
$ npm install -g express-generator
For example, the following creates an Express app named myapp. The app will be created in a folder named myapp in the current working directory and the view engine will be set to Pug:
$ express --view=pug myapp

   create : myapp
   create : myapp/package.json
   create : myapp/app.js
   create : myapp/public
   create : myapp/public/javascripts
   create : myapp/public/images
   create : myapp/routes
   create : myapp/routes/index.js
   create : myapp/routes/users.js
   create : myapp/public/stylesheets
   create : myapp/public/stylesheets/style.css
   create : myapp/views
   create : myapp/views/index.pug
   create : myapp/views/layout.pug
   create : myapp/views/error.pug
   create : myapp/bin
   create : myapp/bin/www
Then install dependencies:
$ cd myapp
$ npm install
On MacOS or Linux, run the app with this command:
$ DEBUG=myapp:* npm start
On Windows Command Prompt, use this command:
> set DEBUG=myapp:* & npm start
On Windows PowerShell, use this command:
PS> $env:DEBUG='myapp:*'; npm start
Then load http://localhost:3000/ in your browser to access the app.
The generated app has the following directory structure:
.
├── app.js
├── bin
│   └── www
├── package.json
├── public
│   ├── images
│   ├── javascripts
│   └── stylesheets
│       └── style.css
├── routes
│   ├── index.js
│   └── users.js
└── views
    ├── error.pug
    ├── index.pug
    └── layout.pug

7 directories, 9 files
The app structure created by the generator is just one of many ways to structure Express apps. Feel free to use this structure or modify it to best suit your needs.

                                    const http = require('http')
const express = require('express')

const app = express()
const server = http.Server(app)
app.set('port', 8888)
server.listen(8888)

app.get('/', (req, res) => {
  res.json({teste: true})
})

                                    // this is your code
// ZDev1#4511 on discord if you want more help!
// first you should install express in the terminal
// `npm i express`.
const express = require('express');
const app = express();

// route
app.get('/', (req,res)=>{
  // Sending This is the home page! in the page
  res.send('This is the home page!');
});

// Listening to the port
let PORT = 3000;
app.listen(PORT)

// FINISH!

                                    // 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}`);
});