1475870 - Provide an alternative to event.composedPath() including closed shadow DOMs

Status: UNCONFIRMED

(WebExtensions :: General, defect, P3)

Description

[mrmr1993]

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:61.0) Gecko/20100101 Firefox/61.0
Build ID: 20180703115938

Steps to reproduce:

This is a follow-up to bug 1439153.

Currently, extensions can find the true target of an event in open shadow DOMs using event.composedPath(). For closed shadow DOMs, event.composedPath() simply gives that the target is the shadow host.

For extensions that depend on knowing this target to work properly, they need an API that does the same as event.composedPath(), but also includes nodes within closed shadow DOMs. This could be exposed only to extensions, as e.g. event.openOrClosedComposedPath (analogous to bug 1439153's openOrClosedShadowRoot).

Comment 1

[Olli Pettay [:smaug][[e-mail]](vacation until Nov 16)]

This should be easy to do now, but shouldn't block shipping, since this can be polyfilled.

Comment 2

[mrmr1993]

Attachment: Add Event.prototype.piercingComposedPath for extensions and chrome