Worker Threads enable true parallelism in Node.js, perfect for CPU-intensive tasks. Let's dive in.

Why Worker Threads?

1. Parallel execution of JavaScript code
2. Shared memory capabilities
3. Ideal for CPU-bound operations

Basic Usage

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

if (isMainThread) {
  const worker = new Worker(__filename);
  worker.on('message', (msg) => console.log('From worker:', msg));
  worker.postMessage('Hello, Worker!');
} else {
  parentPort.on('message', (msg) => {
    console.log('From main:', msg);
    parentPort.postMessage('Hello, Main!');
  });
}

Passing Data

1. Structured Clone Algorithm (default)
2. Transferable objects
3. SharedArrayBuffer for zero-copy transfers

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

const worker = new Worker('./worker.js');

const sharedBuffer = new SharedArrayBuffer(4);
const arr = new Int32Array(sharedBuffer);
arr[0] = 123;

worker.postMessage({ sharedBuffer });

Worker Pools

const { StaticPool } = require('node-worker-threads-pool');

const pool = new StaticPool({
  size: 4,
  task: (n) => n * 2
});

async function runTasks() {
  const results = await Promise.all([
    pool.exec(10),
    pool.exec(20),
    pool.exec(30)
  ]);
  console.log(results); // [20, 40, 60]
}

runTasks().catch(console.error);

Best Practices

1. Use for CPU-intensive tasks, not I/O operations
2. Implement proper error handling
3. Carefully manage shared resources to avoid race conditions
4. Consider using worker pools for better resource management

Performance Considerations

1. Thread creation has overhead; reuse workers when possible
2. Balance number of workers with available CPU cores
3. Minimize data transfer between threads

Pitfalls to Avoid

1. Overusing for simple tasks (threading has overhead)
2. Neglecting to terminate workers when done
3. Assuming automatic load balancing (you must manage this)

Worker Threads shine for parallel processing of CPU-intensive tasks. Use wisely to supercharge your Node.js applications.

Cheers🥂