v148 · JavaScript · Web Workers
Worker Lifecycle Demo
A visual state machine for the Shared Worker lifecycle — from starting to keepalive to terminated. Simulate clients connecting and disconnecting, trigger keepalive events, and watch the timeline.
Checking SharedWorker support…
Worker state machine
starting
→
running
→
keepalive
→
terminating
→
terminated
Worker state
—
Connected clients
0
Worker uptime
0s
Simulation controls
Worker uptime vs. client count timeline
Worker not started
Lifetime extension triggers
| Trigger | Description | Status in simulation |
|---|---|---|
event.waitUntil(fetch(…)) |
A pending fetch() inside the worker keeps it alive |
inactive |
extendedLifetime: true |
Constructor option to request extended lifetime support | inactive |
| Notification pending | Worker requested to show a notification that hasn't been dismissed | inactive |
| Push message in-flight | Worker processing a push message from the Push API | inactive |
Event log
--:--:--Simulation ready. Click "Spawn worker" to start.
see also
implementation reference
Need the exact API surface, compatibility boundaries, errors, lifecycle, and source links? Read the matching gendn reference ↗