Worker Threads

¿Cuándo usar Worker Threads?

Node.js es single‑threaded para JavaScript. Cuando tienes tareas CPU intensivas, los worker threads permiten paralelizar sin bloquear el event loop.

Ejemplo básico

const { Worker, isMainThread, parentPort, workerData } = require('worker_threads');

if (isMainThread) {
  const worker = new Worker(__filename, { workerData: 42 });
  worker.on('message', (result) => console.log('Resultado:', result));
} else {
  const result = workerData * 2;
  parentPort.postMessage(result);
}

Pasar datos grandes

const { Worker } = require('worker_threads');

const buffer = new SharedArrayBuffer(1024);
const view = new Uint8Array(buffer);

const worker = new Worker('./worker.js', { workerData: buffer });
view[0] = 7;

SharedArrayBuffer permite compartir memoria sin copiar.

Pool de workers

class WorkerPool {
  constructor(size, filename) {
    this.workers = Array.from({ length: size }, () => new Worker(filename));
    this.queue = [];
    this.idle = [...this.workers];
  }

  runTask(data) {
    return new Promise((resolve) => {
      const task = { data, resolve };
      this.queue.push(task);
      this._next();
    });
  }

  _next() {
    if (!this.idle.length || !this.queue.length) return;
    const worker = this.idle.pop();
    const task = this.queue.shift();
    worker.once('message', (result) => {
      task.resolve(result);
      this.idle.push(worker);
      this._next();
    });
    worker.postMessage(task.data);
  }
}