Introduction
JavaScript is single-threaded, but Web Workers let you execute code in parallel threads. Ideal for expensive operations that shouldn't block the UI.
What are Web Workers
They are scripts that run in a separate thread from the main thread. They communicate with the main thread via messages using postMessage and onmessage.
Types of Workers
There are several types: Dedicated Workers (single use), Shared Workers (shared between windows), and Service Workers (for network and cache).
Use Cases
Image processing, audio manipulation, data encryption, large file parsing, and complex real-time calculations.
Communication with Main Thread
Use postMessage to send data and listen with onmessage. Data is copied (not shared) using the structured clone algorithm.
Transferables
For large objects like ArrayBuffer, use transferable to move ownership without copying. Much faster for binary data.
Conclusion
Web Workers are essential for data-intensive applications. At Vynta, we use them to keep the UI responsive even under heavy loads.