Intent to implement: Custom Elements v1

[Hayato Ito]

Contact emails hay...@chromium.org Spec https://w3c.github.io/webcomponents/spec/custom/ Summary Implement new Custom Elements APIs, called v1, based on the consensus we reached at the F2F meeting in January [1]. We have a rewrite of the spec based on this meeting [2]. Note that Blink has already shipped Custom Elements, which should be now called v0.

Motivation

All browser vendors reached consensus on many pressing matters about Custom Elements.

There are still active discussions on the spec, https://github.com/w3c/webcomponents/labels/v1, however, I think it's okay to start to implement Custom Element v1.

Interoperability risk Firefox: No public signals Edge: No public signals Safari: In development: https://bugs.webkit.org/show_bug.cgi?id=154907

Web developers: No signals Compatibility risk No. We will have a new API, called document.defineElement() to define custom elements for v1.

The current API, document.registerElement() is unchanged, basically.

The situation is very similar to what happened to Shadow DOM.

Ongoing technical constraints

None Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)? Yes or no. Yes

OWP launch tracking bug https://bugs.chromium.org/p/chromium/issues/detail?id=594918 Link to entry on the Chrome Platform Status https://www.chromestatus.com/features/4696261944934400 Requesting approval to ship?

No

[1] https://www.w3.org/2016/01/26-webapps-minutes.html [2] https://github.com/w3c/webcomponents/pull/405