expressjs route parameters code example

Example 1: express hello world

//to run : node filename.js
const express = require('express')
const app = express()
const port = 3000

app.get('/', (req, res) => res.send('Hello World!'))

app.listen(port, () => console.log(`Example app listening at http://localhost:${port}`))

//visit localhost:3000
// assuming you have done 1) npm init 2) npm install express

Example 2: express get url parameters

app.get('/path/:name', function(req, res) {
  res.send("tagId is set to " + req.params.name);
});

Example 3: node js express url parameters

// http://localhost:8080/api/1
app.get('/api/:version', function(req, res) {
    res.send(req.params.version);
});

Example 4: express route parameters

app.get('/users/:userId/books/:bookId', function (req, res) {
  res.send(req.params)
})

Example 5: express route parameters

Route path: /users/:userId/books/:bookId
Request URL: http://localhost:3000/users/34/books/8989
req.params: { "userId": "34", "bookId": "8989" }

Example 6: 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