Junior From PDF JavaScript JavaScript

What is a service worker?

Short answer: A service worker is a background script that runs independently of the web page. It enables offline caching, push notifications, and background sync.

Example code

navigator.serviceWorker.register('/sw.js'); ✅ Used in Progressive Web Apps (PWAs).

Real-world example (ShopNest)

ShopNest’s browser cart uses modern JavaScript: fetch APIs with async/await, modules, and clear error handling.

Say this in the interview

  1. Define — one clear sentence (the short answer above).
  2. Example — relate it to a project like ShopNest or your real work.
  3. Trade-off — when you would not use it.
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