Patterns in directing events to particular globals

event-targeting.md

Patterns in directing events to particular globals

Push

The push event is only dispatched to a ServiceWorkerGlobalScope. Events are registered by calling serviceWorkerRegistration.pushManager.subscribe(...).

Background sync

The sync event is only dispatched to a ServiceWorkerGlobalScope. Events are registered by calling serviceWorkerRegistration.sync.register(...).

Notifications

Persistent notifications dispatch events to a ServiceWorkerGlobalScope, while non-persistent notifications dispatch them to a Notification in a Window's realm. new Notification() creates a non-persistent notification, while serviceWorkerRegistration.showNotification() creates a persistent one.

So, different spellings for the different event targets, and no way to direct an event to a Worker or SharedWorker.

https://notifications.spec.whatwg.org/#create-a-notification

Worklets

Most Worklets don't handle events registered from Windows.

• paintWorklet is called when CSS uses the paint(name) function.
• renderWorklet is called when CSS uses the *layout(name) functions.

AudioWorklet

The AudioWorklet proposal includes a AudioWorkletNode(..., "name", ...).postMessage() function that causes a call to the onmessage() member of an AudioWorkletProcessor subclass registered for "name", running in an AudioWorkletGlobalScope. This matches the pattern of calling a method on a main-window representation of a worker to cause an event to happen on an instance of that worker.