Q1. What is Express.js and why use it?
Express.js is a minimal and flexible web application framework for Node.js. It provides a robust set of features for building web and mobile applications, including routing, middleware support, template engines, and easier request/response handling. It abstracts away the complexity of raw Node.js HTTP server code, making development faster and more organized.
Q2. How does Express simplify building web servers?
Express provides a simpler API for routing (app.get, app.post), middleware for parsing bodies (express.json()), static file serving (express.static()), and error handling. Instead of manually parsing URLs and methods, Express handles routing. Instead of collecting chunks for body, you use middleware. This reduces boilerplate significantly.
Q3. What are the key features of Express?
Key features: robust routing, middleware support, template engine integration, static file serving, error handling, and easy database connectivity. Express is also highly extensible through third-party middleware. It's the foundation of many Node.js frameworks and is widely used in production.
Q4. How do you create a basic Express server?
Install express: npm install express. Then:
const express = require('express');
const app = express();
app.get('/', (req, res) => res.send('Hello'));
app.listen(3000, () => console.log('Server running'));
Q5. When would you use Express vs raw Node.js?
Use Express for most web applications and APIs because it speeds up development and provides structure. Use raw Node.js when you need maximum control, minimal overhead (micro-frameworks), or for learning purposes. Express is built on Node.js, so you can always drop down to raw features when needed.