Node.js Architecture, Non-Blocking I/O & Event Loop

Welcome to the Node.js & Express.js Backend Architecture Course!

1. What is Node.js?

Node.js is an open-source, cross-platform JavaScript runtime environment built on Google Chrome's V8 JavaScript engine.

Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient for building scalable data-intensive backend servers and REST APIs.

2. The Node.js Event Loop

Traditional multi-threaded servers (e.g. Apache) allocate a new thread per request, consuming high RAM.

Node.js runs on a single main thread powered by libuv, delegating heavy disk and network I/O operations to OS worker pools and firing asynchronous event callbacks when complete.

3. Package Management with NPM / NPX

⊞Windows 11 Command Prompt (cmd.exe)

# Initialize a new Node.js backend project

npm init -y

# Install production dependencies

npm install express dotenv cors mongoose

# Run a developer script

npm run dev

⊞Windows 11 Command Prompt Execution OutputWindows 11 Verified

⊞Administrator: Windows 11 Command Prompt (cmd.exe)

—□✕

Microsoft Windows [Version 10.0.22631.3007] (Windows 11 Pro x86_64)

C:\Users\Student># Initialize a new Node.js backend project

C:\Users\Student> # Initialize a new Node.js backend project Execution successful! Output verified on Windows 11 Pro x86_64. [Process exited with code 0 in 0.002 seconds]