Worker Threads

ELI5 — The Vibe Check

Worker Threads let Node.js actually use more than one CPU core. Normally Node is single-threaded — it can only do one heavy calculation at a time. Worker Threads are like hiring extra brains to do the math homework while the main thread keeps answering HTTP requests.

Real Talk

Worker Threads is a Node.js module that enables true parallel execution of JavaScript code in separate threads sharing the same process memory. Unlike child processes, workers can share memory via SharedArrayBuffer and communicate efficiently through message passing. Ideal for CPU-intensive tasks that would otherwise block the event loop.

Show Me The Code

const { Worker } = require('worker_threads');
const worker = new Worker('./heavy-calc.js', { workerData: { input: data } });
worker.on('message', (result) => console.log('Done:', result));
worker.on('error', (err) => console.error(err));

When You'll Hear This

"We offload image processing to Worker Threads so the API stays responsive." / "Worker Threads share memory, making them faster than child processes for CPU work."