Node.js Express Framework

Express is a fast and minimal web framework for Node.js, designed to simplify the process of building web applications and APIs. It provides robust features for routing, middleware integration, and handling HTTP requests, making it the go-to framework for building server-side applications in Node.js.

 

Key Features of Express Framework

1. Simplifies server setup and request handling.
2. Provides a robust routing mechanism for defining application endpoints.
3. Supports middleware for custom request and response processing.
4. Offers seamless integration with databases and template engines.

 

Installing Express

Initialize a Node.js project:

npm init -y 

Install Express:

npm install express  

 

Creating a Basic Express Server

Code Example
Create server.js:

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

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

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

Run the server:

node server.js  

Visit http://localhost:3000 in your browser to see the message.

Adding Middleware

Middleware functions process requests and responses.

// Middleware to log requests  
app.use((req, res, next) => {  
  console.log(`${req.method} ${req.url}`);  
  next();  
});  

app.get('/', (req, res) => {  
  res.send('Middleware Example');  
});  

Routing in Express

Define multiple routes for different endpoints.

app.get('/about', (req, res) => {  
  res.send('About Page');  
});  

app.post('/submit', (req, res) => {  
  res.send('Form Submitted');  
});  

 

Summary

Express is a powerful framework that simplifies web application development in Node.js. With its easy-to-use routing, middleware support, and extensibility, developers can quickly build robust and scalable server-side applications. It remains one of the most popular choices for Node.js developers worldwide.