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Intermediate 16 min readModule: Module 2: Core Modules (fs, path, events, os)

File System (fs/promises) & EventEmitter

Read and write files asynchronously with fs/promises, resolve cross-platform paths with path, and publish custom events.

What You Will Learn in This Lesson

  • Reading/writing files asynchronously with fs.promises
  • Resolving cross-platform file paths using path.join and path.resolve
  • Building event-driven architectures with EventEmitter

Introduction & Core Concept

Node.js comes bundled with core standard library modules for interacting directly with the filesystem, operating system, and process environment.
WHY DOES THIS MATTER IN THE REAL WORLD?

Using fs.promises avoids blocking the event loop while reading files from disk.

Async File Reading with fs/promises

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const fs = require("fs/promises");
const path = require("path");
 
async function loadConfig() {
  const configPath = path.join(__dirname, "config.json");
  const rawData = await fs.readFile(configPath, "utf-8");
  return JSON.parse(rawData);
}
console.log("File system utilities loaded.");

Line-by-Line Technical Breakdown

1EventEmitter enables decoupled pub/sub architectures across backend subsystems.

Try It Yourself (Interactive Editor)

Modify the code in real-time and click Run to test live browser output and console logs.

Intelligent Code Runner & Live Sandbox[JAVASCRIPT]
JAVASCRIPT SOURCE EDITOR
Interactive Live Code

Industry Best Practices & Professional Standards

  • Never use synchronous methods like fs.readFileSync in production servers.

Lesson Summary & Core Takeaways

  • Core modules provide native access to the operating system and filesystem.