how to start a express server in node js code 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: 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}`));