FrontendHigh signalAround since 2014
Service Worker
A script that runs in the background of a browser tab, separate from the page itself, enabling offline support, caching, and push notifications for web apps.
Think of it like
Like a store's night-shift stock clerk who keeps the shelves ready even when the front doors are locked, so regular customers can still grab what's cached.
Junior or senior?
Junior sounds like
Says the app 'works offline' via a PWA without further detail.
Senior sounds like
Can describe the actual service worker cache-invalidation strategy — how a stale asset got updated.
Ask them
“How did you handle updating a cached asset once you shipped a new version of your app?”