✅ Express.js Basics You Should Know 🚀📦

Express.js is a fast, minimal, and flexible Node.js web framework used to build APIs and web apps.

1️⃣ What is Express.js? 🏗️
A lightweight framework on top of Node.js that simplifies routing, middleware, request handling, and more.

2️⃣ Install Express: 📦

npm init -y
npm install express

3️⃣ Basic Server Setup: 🚀

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

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

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

4️⃣ Handling Different Routes: 🗺️

app.get('/about', (req, res) => res.send('About Page'));
app.post('/submit', (req, res) => res.send('Form submitted'));

5️⃣ Middleware: ⚙️
Functions that run before a request reaches the route handler.

app.use(express.json()); // Example: Parse JSON body

6️⃣ Route Parameters & Query Strings: ❓

app.get('/user/:id', (req, res) => {
  res.send(`User ID: ${req.params.id}`); // Access route parameter
});

app.get('/search', (req, res) =>
  res.send(`You searched for: ${req.query.q}`); // Access query string
);

7️⃣ Serving Static Files: 📁

app.use(express.static('public')); // Serves files from the 'public' directory

8️⃣ Sending JSON Response: 📊

app.get('/api', (req, res) => {
  res.json({ message: 'Hello API' }); // Sends JSON response
});

9️⃣ Error Handling: ⚠️

app.use((err, req, res, next) => {
  console.error(err.stack); // Log the error for debugging
  res.status(500).send('Something broke!'); // Send a generic error response
});

🔟 Real Projects You Can Build: 📝
- RESTful APIs
- To-Do or Notes app backend
- Auth system (JWT)
- Blog backend with MongoDB

💡 Tip: Master your tools to boost efficiency and build better web apps, faster.

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