We can create a server using Express (a Node module) using the code snippet below:

// Import the express library
const express = require("express")

// Loads environment variables from a .env file into process.env
require("dotenv").config()

// Instantiate the app
const app = express()

const PORT = process.env.PORT || 8000

// Invoke the app's `.listen()` method below:
app.listen(PORT, () => {
  console.log(`Server listening on port ${PORT}`)
})

LINE-2: We import the Express library with require.

LINE-8: We return an instance of an Express application.

LINE-13: We tell the server where to listen for new requests by providing a port number argument to a method called app.listen(). The server will then listen on the specified port and respond to any requests that come into it. The second argument is a callback function that will be called once the server is running and ready to receive requests.

In our example above, our app.listen() call will start a server listening on port 5000, and once the server is started it will log Server listening on port 5000.