Master programming syntax, solve interactive challenges & run live code in Syntaxis Explore Arena →

menu_book Course Curriculum (Node.js) expand_more

Runtime & Modules

process.argv process.env CommonJS require CommonJS exports ES module import ES module export import.meta.url dynamic import

Filesystem

readFile writeFile appendFile mkdir recursive readdir stat createReadStream createWriteStream

Paths & URLs

path.join path.resolve path.extname path.basename URL constructor URLSearchParams fileURLToPath pathToFileURL

Events & Buffers

EventEmitter on emit EventEmitter once Buffer from string Buffer concat Buffer slice TextDecoder Readable stream Transform stream

HTTP

http.createServer Parse request URL Read request body JSON response Status code Response headers Streaming response Abort request

Async & Processes

Promise API async await setImmediate process.nextTick AbortController child_process execFile spawn process worker_threads

Testing & Diagnostics

node:test basic test assert strictEqual mock timer concept process warning console time performance.now unhandledRejection handler uncaughtException monitor

Production

Graceful shutdown Health endpoint Environment config Structured log object Cluster concept Rate-limit concept Cache headers Signal handling

Node.js / Events & Buffers

EventEmitter once

Learn EventEmitter once in Node.js with a dedicated explanation, a topic-specific example, edge guidance, and a mastery check.

12 min read • Intermediate

nodejs-026.js

javascript

import { EventEmitter } from "node:events"; const bus=new EventEmitter(); bus.once("ready",()=>console.log("first only")); bus.emit("ready"); bus.emit("ready");

What to watch

Content source & attribution

Original Syntaxis Content · Original Syntaxis Content

Lesson quizzes

EventEmitter once Mastery Check →

EventEmitter on emit

Buffer from string