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JavaScript Academy · Lesson

Use Cases and Limitations

Know when workers help and what they cannot do.

What Workers Are Good For

Web Workers shine when you have CPU-heavy work that would otherwise freeze the UI:

  • Image and video processing
  • Parsing large files (CSV, JSON)
  • Cryptography and hashing
  • Physics, data analysis, and simulations

No DOM Access

The biggest limitation: workers cannot touch the DOM. There is no document or window. They compute data and send it back; the main thread updates the UI.

// Inside a worker:
// document.querySelector(...) -> ReferenceError
// Workers have no DOM at all.

All lessons in this course

  1. Creating a Web Worker
  2. Messaging with postMessage
  3. Transferable Objects
  4. Use Cases and Limitations
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