create simple node server with express code example

Example 1: create server with express js

// 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}`);
});

Example 2: 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 3: simple express server

const express = require('express');
const app = express();
const mongoose = require('mongoose');
const bodyParser = require('body-parser');

app.use(bodyParser.json());
const PORT = process.env.PORT || 3000;

app.use(bodyParser.json());

//connecting to db
try {
    mongoose.connect('mongodb://localhost/YOUR_DB_NAME', {
        useNewUrlParser: true,
        useUnifiedTopology: true,
      	useCreateIndex: true,
      }, () =>
      console.log("connected"));
  } catch (error) {
    console.log("could not connect");
  }

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}`));