Why we need express framework when we have http, https and http2 modules in Node.js

Express.js is a web framework for Node.js that simplifies the process of building web applications and APIs. While Node.js provides core modules like http, https, and http2 for handling HTTP requests and responses, Express.js offers several advantages that make it a preferred choice for many developers:

Key Reasons for Using Express.js

1. Middleware: Express.js provides a middleware layer that allows you to manage and process incoming requests before they reach your routes. Middleware functions can perform tasks such as parsing request bodies, handling cookies, logging requests, and more. This modular approach simplifies the handling of complex request processing logic.

2. Routing: Express.js offers a robust routing system that allows you to define routes based on HTTP methods and URL paths. This makes it easy to organize your application into logical routes and handlers, enhancing code readability and maintainability.

3. Simpler Syntax: Express.js provides a simpler and more expressive syntax compared to using Node.js core modules directly. It reduces boilerplate code and provides convenient methods for common tasks such as sending responses, handling errors, and rendering views.

4. Template Engines: Express.js supports various template engines (like EJS, Pug, Handlebars) out of the box, making it easier to generate HTML dynamically based on data from your application.

5. Integration with Middleware: It's easy to integrate third-party middleware or libraries with Express.js, allowing you to add functionalities like authentication, session management, caching, and more without reinventing the wheel.

6. Community and Ecosystem: Express.js has a large and active community with many open-source middleware and modules available. This ecosystem provides solutions and best practices for common web development challenges, speeding up development time.

Example of Using Express.js

Here's a simple example to illustrate how Express.js simplifies creating an HTTP server compared to using Node.js core http module directly:

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

// Define a route
app.get('/', (req, res) => {
  res.send('Hello, Express!');
});

// Start the server
const port = 3000;
app.listen(port, () => {
  console.log(`Express server running at http://localhost:${port}`);
});

Comparison with Node.js Core Modules

• HTTP/HTTPS/HTTP2 Modules: Node.js core modules (http, https, http2) provide basic functionality for handling HTTP requests and responses. While they are powerful and suitable for building simple servers, they lack higher-level features such as routing, middleware support, and easier error handling.

• Express.js: Express.js builds on top of these core modules, abstracting away low-level details and providing a more structured and organized way to build web applications. It allows developers to focus on application logic rather than managing protocol-level intricacies.

When to Use Express.js

• Building APIs: Express.js is excellent for building RESTful APIs or GraphQL APIs due to its robust routing system and middleware support.

• Web Applications: For building web applications with dynamic server-side rendering or using client-side frameworks (like React, Angular, Vue), Express.js provides the necessary tools for handling routes, rendering views, and managing state.

• Microservices: Express.js is suitable for building microservices that communicate over HTTP/HTTPS, allowing you to quickly spin up lightweight services that perform specific tasks.