showNotification() throwing exceptions

[beverloo]

(editorial)

https://notifications.spec.whatwg.org/#dom-serviceworkerregistration-shownotification

(1) Let promise be a new promise.
(2) Let notification be the result of creating a notification given title and options. Rethrow any exceptions.
(3) If context object's active worker is null, reject promise with a TypeError exception.

I see that WebIDL defines some additional steps for promises - if a function returning a Promise value throws an exception, rather than throwing the exception it'll reject the promise.

Can we change the showNotification() algorithm to point this out explicitly? I found this rather confusing, and it took me quite a while to figure out where that behavior comes from.

Loosely following the fetch spec's formulation, what about the following amendment to the showNotification() steps?

1. Let notification be the result of creating a notification given title and options. If that threw an exception, reject promise with that exception.

[annevk]

Seems okay. Should probably merge the bikeshed thing first.