Worker Thread

What are Worker Threads?

Node.js runs JavaScript in a single thread called the event loop, handling one main task at a time.

The Problem: If a task takes too long (like heavy calculations), the event loop gets blocked and the app becomes slow.

The Solution: Worker threads are helpers that run code in the background. They allow your main thread to keep working while heavy work runs separately.

How It Works

• Use the worker_threads module
• Each worker runs JavaScript in its own thread and memory space
• Main thread and worker communicate using messages

When to Use

Use worker threads for CPU-heavy tasks like:

• Image or video processing
• Complex math
• Data compression

Do not use for normal file or network tasks (Node already handles those well).

Interview Questions

Q: What is a worker thread in Node.js?
A worker thread runs JavaScript in parallel threads. It helps handle CPU-heavy tasks without blocking the main event loop.

Q: When should you use worker threads?
Use them for CPU-heavy operations that slow the main thread.

Q: Difference between worker thread and child process?
Worker threads share memory within the same process. Child processes run in separate processes and do not share memory.