Introduction to Express.js

Express.js is a minimalist, unopinionated web application framework for Node.js. It provides a simple API for handling routes, middleware, and HTTP requests, making it easier to build web serves and APIs. With Express, you can quickly set up server-side logic, respond to client requests, and integrate with various template engines and databases.

Why Use Express?

• Simplicity & Minimalism:
  Express offers a lean core that lets you build your server without unnecessary overhead. You add functionality via middleware and plugins as needed.
• Flexibility:
  Its unopinionated design means you’re free to structure your project as you see fit. Whether you want a full MVC architecture or a simple API, Express adapts to your needs.
• Robust Routing:
  Express provides a powerful and intuitive routing system, making it simple to define URL patterns and handle HTTP methods (GET, POST, etc.).
• Extensive Ecosystem:
  Thanks to npm, there’s a vast collection of third-party middleware and packages (e.g., for authentication, logging, error handling) that extend Express’s functionality.
• Community Support:
  Being one of the most popular Node.js frameworks, Express has extensive documentation, tutorials, and community support available

Installation and Setup

Prerequisites

• Node.js and npm:
  • Ensure you have Node.js installed. npm (Node Package Manager) comes bundled with Node.js.

Step to Install Express

1 Initialize a New Project:

Open your terminal and create a new directory.

mkdir my-express-app
cd my-express-app

Initialize a new Node.js project:

npm init -y

2 Install Express:

Install Express using npm:

npm install express

3 Create a Basic Server:

Create a file called app.js and add the following code:

// Import Express module
const express = require('express');
const app = express();
const port = 3000;

// Define a route handler for the default home page
app.get('/', (req, res) => {
  res.send('Hello, World!');
});

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

4 Run the Server:

Start your application by running:

node app.js

Open the browser and navigate to http://localhost:3000 to see your Express server in action.