what does express.router() do code example

Example 1: express mounting router

var express = require('express')
var router = express.Router()

// middleware that is specific to this router
router.use(function timeLog (req, res, next) {
  console.log('Time: ', Date.now())
  next()
})
// define the home page route
router.get('/', function (req, res) {
  res.send('Birds home page')
})
// define the about route
router.get('/about', function (req, res) {
  res.send('About birds')
})

module.exports = router

Example 2: nodejs express routing

// You need to install the following packages
npm install --save mysql express
// And if you don't want to restart your server after every little change
npm install -g nodemon