Lesson 2.1:
Node.js v26 Internals

The V8 Engine & Event Loop

By v26, Node.js has optimized the event loop for even lower latency. Understanding the phases of the event loop is critical for building non-blocking services.

Worker Threads & Shared Memory

True parallelism is achieved using Worker threads. For ultra-high performance, SharedArrayBuffer allows workers to access the same memory without copying.

import { Worker, isMainThread, parentPort } from 'node:worker_threads';

if (isMainThread) {
  const sab = new SharedArrayBuffer(1024);
  const worker = new Worker(new URL(import.meta.url), { workerData: sab });
} else {
  // Access data directly from memory
}

Native ESM Resolution

v26 treats ESM as the primary citizen. The loader handles complex dependency trees natively, often faster than older bundlers.

Check Your Knowledge

Which mechanism allows threads to share memory in Node.js?

• SharedArrayBuffer
• JSON.stringify