document.caretPositionFromPoint API

[siliu1]

WebKittens

@pxlcoder @rniwa @whsieh

Title of the spec

CSSOM View: document.caretPositionFromPoint()

URL to the spec

https://www.w3.org/TR/cssom-view-1/#dom-document-caretpositionfrompoint

URL to the spec's repository

No response

Issue Tracker URL

No response

Explainer URL

No response

TAG Design Review URL

No response

Mozilla standards-positions issue URL

No response

WebKit Bugzilla URL

https://bugs.webkit.org/show_bug.cgi?id=172137

Radar URL

No response

Description

WebKit/Blink has similar document.caretRangeFromPoint API which returns a text range indicating the text insertion point. The existing API was in CSSOM View at the time it was implemented: https://web.archive.org/web/20090708002518/http://dev.w3.org/csswg/cssom-view/#the-documentview-interface

The existing API was replaced by the new API later: https://hg.csswg.org/drafts/rev/4c7b6f843171

Gecko already implemented the new API.

[Ahmad-S792]

Bugzilla Ticket: https://bugs.webkit.org/show_bug.cgi?id=172137

[annevk]

Bit sad that nobody improved upon my 2009 definition of this method.

One thing that's not clear to me looking at this today is what happens if node tree mutations happen after you invoke this method. If it's an actual Range underneath, it would be impacted, which would then impact the result of caret position's getClientRect(). Whether that's desirable is a separate question.

[marcoscaceres]

@pxlcoder, @rniwa, @whsieh, any opinions about this?

[siliu1]

CSS working group discussed this API (details in w3c/csswg-drafts#9932). The proposal is to add a new shadowRoots parameter to the API so that only the provided shadow roots can be pierced.

[annevk]

It seems w3c/csswg-drafts#10230 was filed on the issue I mentioned above. Overall this API seems reasonable to me, modulo that issue.

[siliu1]

w3c/csswg-drafts#10307 was merged. CaretPosition is not backed by a live range now. @annevk FYI. Thanks!

[annevk]

w3c/csswg-drafts#10345 modifies the API a bit further.

In any event, I suggest we resolve this as "position: support" one week from now. This API has been standardized for a long time already and this mainly adds support for shadow roots in a manner compatible with other APIs.