Explain Routing in Express.js?

Routing is a mechanism used by frameworks to decide how a URL/endpoint is responded/handled by the server. Express provides an excellent way to handle applications routing. Below is basic code to handle routing in Express.

var express = require('express')
var app = express()

// respond with "hello world" when a GET request is made to the homepage
app.get('/', function (req, res) {
  res.send('hello world')
});