Node.js Complete Study Notes (Exam Version)

Updated: 2026-03-24

1) Read This First

This file is designed for Notion and exam preparation. It focuses on:

• Node.js runtime concepts
• JavaScript and TypeScript data types
• Properties and methods of major built-in types
• TypeScript OOP features (class, interface, enum)
• Entity concept in backend (NestJS + TypeORM style)
• Frequently used Node.js core module functions

Important note: Node.js has a very large API surface. This guide covers the most important and commonly tested APIs in depth.

2) Node.js in One Picture

Node.js is a JavaScript runtime built on V8.

• Single-threaded event loop for JS execution
• Non-blocking I/O via libuv
• Great for API servers and I/O-heavy apps

Execution flow (simplified):

1. JS runs on call stack.
2. Async I/O is delegated to system/libuv.