Intent to Prototype: headingstart attribute.

[Keith Cirkel]

Contact emails

chro...@keithcirkel.co.uk

Explainer

https://github.com/whatwg/html/issues/9881

Specification

(Not yet available) - I will be prototyping out a solution to then specify in HTML.

Summary

This feature proposes `ElementInternals#connectedSignal` which is an `AbortSignal` created when the element is connected to the DOM and aborted when the element disconnects from the DOM.

Blink component

Blink>DOM

Motivation

A common technique for Custom Element authors is add event listeners or fetch requests that are attached to the connected state of an element - typically by passing in an AbortController Signal which is aborted on disconnectedCallback. It can be a little cumbersome to set up such an AbortController, and would simplify ergonomics if Custom Elements had a built-in AbortSignal that represented the connected state.

Initial public proposal

https://github.com/whatwg/html/issues/9881

TAG review

None

TAG review status

Pending

Risks

Interoperability and Compatibility

None

Gecko: No signal

WebKit: No signal

Web developers: Positive

Other signals:

WebView application risks

Does this intent deprecate or change behavior of existing APIs, such that it has potentially high risk for Android WebView-based applications?

None

Debuggability

None

Is this feature fully tested by web-platform-tests?

No

Flag name on chrome://flags

Experimental Web Platform Features

Finch feature name

None

Non-finch justification

None

Requires code in //chrome?

False

Estimated milestones

No milestones specified

Link to entry on the Chrome Platform Status

https://chromestatus.com/feature/5110336687702016

[Keith Cirkel]

Apologies for the copypasta. Subject should read "ElementInternals#connectedSignal" not "headingstart attribute" :)

[Keith Cirkel]

Apologies for the subject copypasta. This is to prototype ElementInternals#connectedSignal _not_ headingstart, which is a separate prototype :)