Remove ServiceWorkerMessageEvent and use MessageEvent to fire message events to ServiceWorkerContainer objects and create custom message events.
As ServiceWorkerMessageEvent and MessageEvent have the same interface definition except the type of the source atttriute, we aim to reduce this platform redundancy by replacing ServiceWorkerMessageEvent with the extended MessageEvent that allows ServiceWorker as a type of the source attribute.
1. Contents creating a ServiceWorkerMessageEvent object using its constructor will raise a ReferenceError.
2. Contents creating a ServiceWorkerMessageEvent object by calling document.createEvent('ServiceWorkerMessageEvent') will throw a DOMException.
3. Contents checking event.type in navigator.serviceWorker.onmessage event listeners will get the value of 'MessageEvent' instead of 'ServiceWorkerMessageEvent'.
The usage counts for 2 and 3 are rounding to zero. The usage count for 1 is not measurable but expected to be very low.
Alternative implementation suggestion for web developers
Use MessageEvent interface instead of ServiceWorkerMessageEvent inteface to create a custom event.
Consider the message events received at navigator.serviceWorker are using MessageEvent interface instead of ServiceWorkerMessageEvent interface.
Usage information from UseCounter
OWP launch tracking bug
Entry on the feature dashboard
I don't seem to have a permission to create an entry. Here's the summary I propose:
Remove ServiceWorkerMessageEvent in favor of using MessageEvent
As HTML spec extended MessageEvent to allow ServiceWorker as a type of the source attribute, client.postMessage(message, transfer) and creation of custom message events are changed to use MessageEvent instead of ServiceWorkerMessageEvent.
Requesting approval to remove too?