🔹 What is Node.js?

Node.js is a JavaScript runtime that allows JavaScript to run outside the browser.

• It is built on the Chrome V8 engine, which converts JavaScript into machine code for fast execution.
  

• Node.js is mainly used to build backend applications, such as web servers, APIs, and real-time applications.
  

Key Features

• Runs JavaScript on the server
  

• Non-blocking I/O (doesn’t freeze the server)
  

• Single-threaded but handles multiple requests efficiently
  

Real-Life Analogy

Think of Node.js as a chef in a kitchen:

• Instead of cooking one dish at a time, the chef can start one dish, then move to another while the first is simmering.
  

• This makes the kitchen (server) fast and efficient, even with many orders (requests).
  

🔹 Node.js Architecture

Node.js uses an event-driven and non-blocking architecture, which makes it highly efficient.

• It uses a single main thread to handle multiple client requests.
  

• When a request comes in, Node.js delegates heavy tasks to background threads and continues processing other requests.
  

Event-Driven Architecture Explained

• Node.js listens for events like a browser listening for clicks.
  

• When an event occurs, the callback function is executed.

🔹 Installing Node.js & npm

Node.js can be installed from the official website: https://nodejs.org

• npm (Node Package Manager) comes bundled with Node.js.

• npm is used to install, manage, and share packages in your Node.js project.