Service Workers provide offline support for web applications. They intercept network requests and can serve cached content when offline.

Key Concepts

• Conceptually: A worker between network and document renderer
• Benefits: Offline support, faster experience, push notifications
• Lifecycle: parsed → installing → installed → activating → activated → redundant

Service Worker States

enum ServiceWorkerState {
  "installing",
  "installed", 
  "activating",
  "activated",
  "redundant"
}

Key Events

• install - Cache assets
• activate - Clean up old caches
• fetch - Intercept network requests

Service Workers enable truly progressive applications on par with—and often better than—native apps!