Express Routing

Relax. We'll talk through this in plain words — no textbook voice.

Routing is about deciding what response the server sends back, based on which URL the user/client calls. In Express, you write routes using the pattern app.METHOD(PATH, HANDLER).

javascript

const express = require('express');
const app = express();

app.get('/', (req, res) => {
  res.send('Homepage');
});

app.get('/about', (req, res) => {
  res.send('About Page');
});

app.get('/products/:id', (req, res) => {
  res.send(`Product ID is ${req.params.id}`);
});

app.post('/login', (req, res) => {
  res.send('Login route received a POST request');
});

app.listen(3000, () => console.log('Routing demo running on port 3000'));

/products/:id, :id is the route parameter. If you go to /products/15 in the browser, req.params.id will be 15.

You should see

GET http://localhost:3000/products/15 Product ID is 15

Info

GET requests are mostly used for reading data, and POST requests for sending data. Form submits, logins, and creating items usually use POST.

Easy traps

Typing a URL into the browser's address bar always sends a GET request. If you want to test a POST route, use Postman, Thunder Client, fetch, a form submit, or something similar.

Exercise

Use routing to structure things like e-commerce product pages, user profile pages, blog detail pages, and admin action endpoints.

You'll know it worked when: