Why advanced patterns matter in Express - See It in Action

Why Advanced Patterns Matter in Express

📖 Scenario: You are building a simple web server using Express.js to handle user requests. As your app grows, you want to organize your code better to keep it clean and easy to maintain.

🎯 Goal: Build an Express server that uses advanced routing patterns with middleware and route grouping to handle requests cleanly and efficiently.

📋 What You'll Learn

Create an Express app with a basic route

Add a middleware function to log request info

Use an Express Router to group user-related routes

Apply middleware only to the user routes

💡 Why This Matters

🌍 Real World

Organizing Express apps with routers and middleware helps keep code clean and maintainable as projects grow.

💼 Career

Understanding advanced Express patterns is essential for backend developers building scalable and secure web servers.

1

Set up the Express app with a basic route

Create an Express app by requiring express and calling express() to create app. Then add a GET route on '/' that sends the text 'Welcome to the homepage'.

Express

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

// Your code here

Need a hint?

Use require('express') to import Express and app.get to create the route.

2

Add a middleware function to log requests

Create a middleware function called logger that logs the HTTP method and URL of each request. Use app.use(logger) to apply it globally.

Express

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

// Your code here

app.get('/', (req, res) => {
  res.send('Welcome to the homepage');
});

Need a hint?

Middleware functions take req, res, and next. Call next() to continue.

3

Use an Express Router to group user routes

Create an Express Router called userRouter. Add two GET routes on '/profile' and '/settings' that send 'User Profile' and 'User Settings' respectively. Mount userRouter on '/user' in the main app.

Express

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

// Your code here

function logger(req, res, next) {
  console.log(`${req.method} ${req.url}`);
  next();
}

app.use(logger);

app.get('/', (req, res) => {
  res.send('Welcome to the homepage');
});

Need a hint?

Use express.Router() to create a router and app.use('/user', userRouter) to mount it.

4

Apply middleware only to user routes

Create a middleware function called userAuth that sends res.status(401).send('Unauthorized') if req.query.token is missing. Apply userAuth only to userRouter routes.

Express

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

// Your code here

function logger(req, res, next) {
  console.log(`${req.method} ${req.url}`);
  next();
}

app.use(logger);

const userRouter = express.Router();

userRouter.get('/profile', (req, res) => {
  res.send('User Profile');
});

userRouter.get('/settings', (req, res) => {
  res.send('User Settings');
});

app.use('/user', userRouter);

app.get('/', (req, res) => {
  res.send('Welcome to the homepage');
});

Need a hint?

Middleware can be applied to routers with userRouter.use(userAuth).