Express.js Tutorial

Express.js is a minimal and flexible Node.js web application framework that provides a list of features for building web and mobile applications easily. It simplifies the development of server-side applications by offering an easy-to-use API for routing, middleware, and HTTP utilities.

• Built on Node.js for fast and scalable server-side development.
• Simplifies routing and middleware handling for web applications.
• Supports building REST APIs, real-time applications, and single-page applications.
• Provides a lightweight structure for flexible and efficient server-side development.

To start with Express.js, you need to install Node.js on your machine. Follow these articles to install depending on your system:

• How to Install Node.js on Windows?
• Installation of Node JS on Linux
• How to Install NodeJS on MacOS
• How to install Express in a Node project?

Let us now take a look at our first code example.

JavaScript

// Import Express
const express = require('express');
const app = express();

// Define a route
app.get('/', (req, res) => {
    res.send('Welcome to the Express.js Tutorial');
});

// Start the server
app.listen(3000, () => {
    console.log('Server is running on http://localhost:3000');
});

It will start a server, and when you visit http://localhost:3000, it will display

Welcome to the Express.js Tutorial

In this example:

• Express is imported using require('express'), and an app instance is created with express().
• A route is defined using the app.get() method, which responds with a message when the root URL (/) is accessed.
• The app.listen() method starts the server and listens on port 3000 for incoming requests.

Why learn Express?

• Simplifies building web servers and APIs.
• Integrates seamlessly with Node.js.
• Offers extensive middleware support.
• Ideal for single-page applications and RESTful APIs.

Express.js Tutorial

Express.js Tutorial Prerequisites: JavaScript, Node.js, and basic web development knowledge

Express Basic

• Introduction to Express
• Steps to create Express Application
• Design first Application using Express
• How to Structure my Application in Express JS 
• Unique features of Express
• How to send response from server to client using Node and Express ?
• Why Express ‘app’ and ‘server’ files kept separately ?
• How to implement JWT authentication in Express app
• How to expire session after 1 min of inactivity in express-session of Express JS
• Express Error Handling

Express Functions

Express express()

• Expresson() Function
• express.raw() Function
• express.Router() Function
• express.static() Function
• express.text() Function
• express.urlencoded() Function
• express() function Complete Reference

Express Applications Function

• app.locals Property
• app.mountpath Property
• Mount Event
• app.all() Function
• app.delete() Function
• app.disable() Function
• app.disabled() Function
• app.enable() Function
• app.enabled() Function
• Application Complete Reference

Express Requests Function

• req.app Property
• req.baseUrl Property
• req.body Property
• req.cookies Property
• req.fresh Property
• req.accepts() Function
• req.acceptsCharsets() Function
• req.acceptsEncodings() Function
• req.acceptsLanguages() Function
• Request Complete Reference

Express Response Function

• res.app Property
• res.headersSent Property
• res.locals Property
• res.append() Function
• res.attachment() Function
• res.cookie() Function
• res.clearCookie() Function
• res.download() Function
• res.end() Function
• Response Complete Reference

Express Router Function

• router.all() Function
• router.METHOD() Function
• router.param() function
• router.route() Function
• router.use() Function
• Router Complete Reference

Express Advanced Topics

• Node vs Express
• Middlewares in Express
• How to update record in Cassandra using Express 
• What is the use of next() function in Express JS
• How to create custom middleware in express
• Why Express is used in Web Development
• What is Express Generator
• Express HTTP methods
• How to create routes using Express and Postman?
• Why Express Is Used For Enterprise App Development
• REST API using the Express to perform CRUD
• What is express-session middleware in Express

Express.js For Interview

• Top 50 Express.js Interview Questions and Answers
• Learn Express
• Express JS Exercises, Practice Questions and Solutions

Key Features of Express

1. Middleware and Routing: Define clear pathways (routes) within your application to handle incoming HTTP requests (GET, POST, PUT, DELETE).
2. Minimalistic Design: Express.js follows a simple and minimalistic design philosophy. This simplicity allows you to quickly set up a server, define routes, and handle HTTP requests efficiently.
3. Flexibility and Customization: Express.js doesn’t impose a strict application architecture. You can structure your code according to your preferences.
4. Templating Power: Incorporate templating engines like Jade or EJS to generate dynamic HTML content, enhancing user experience.
5. Static File Serving: Effortlessly serve static files like images, CSS, and JavaScript from a designated directory within your application.
6. Node.js Integration: Express.js seamlessly integrates with the core functionalities of Node.js, allowing you to harness the power of asynchronous programming and event-driven architecture.

Applications of Express

Express.js empowers you to construct a wide array of web applications. Here are some captivating examples:

• RESTful APIs: Develop robust APIs that adhere to the REST architectural style, enabling communication with other applications and front-end interfaces.
• Real-time Applications: Leverage Express.js's event-driven nature to create real-time applications like chat or collaborative editing tools.
• Single-Page Applications (SPAs): Craft SPAs that fetch and update content dynamically on the client-side, offering a seamless user experience.

Express.js vs Other Frameworks

Feature	Express.js	Django	Ruby on Rails
Language	JavaScript	Python	Ruby
Flexibility	High (Unopinionated)	Moderate (Opinionated)	Low (Highly Opinionated)
Performance	High	Moderate	Moderate
Middleware Support	Extensive	Limited	Limited
Use Case	APIs, Web Apps	Full-stack Development	Full-stack Development