Intent to Prototype: AbortSignal.any()

[Scott Haseley]

Contact emails

shas...@chromium.org

Explainer

https://github.com/shaseley/abort-signal-any/blob/main/README.md

Specification

The spec work is in progress; I'll send out PRs when I make progress on implementation and tests. Rough drafts:

AbortSignal.any(): https://github.com/shaseley/dom/commit/f0114bf2a0a7d8cc49fff004befbc0d442d1da63
TaskSignal.any(): https://github.com/shaseley/scheduling-apis/commit/b732d365c4f466098392b397da5cb71ac5237b6c

Design docs

https://docs.google.com/document/d/1LvmsBLV85p-PhSGvTH-YwgD6onuhh1VXLg8jPlH32H4/edit#heading=h.xp6e50wyimb4

Summary

AbortSignal.any(signals) returns a signal that is aborted when any of the source signals are aborted. Developers can use this to combine independent abort sources, e.g. timeouts specified with AbortSignal.timeout() and signals associated with user input, and pass them to async APIs like fetch().

Blink component

Blink>DOM

Motivation

Some async operations may be aborted due to a variety of reasons, e.g. due to timeout or user cancellation. And while nothing prevents an AbortController's abort method from being invoked for multiple reasons, combining signals enables separate layers of control, where the scope of cancellation may vary. Since AbortSignal-accepting APIs only accept a single signal, combining signals currently needs to be done in userland using event listeners, but this is complicated by challenges around memory leaks. AbortSignal.any() makes it easy to combine signals, and by allowing the UA to maintain these relationships, the UA can free related resources when safe to do so.

Initial public proposal

https://github.com/whatwg/dom/issues/920

TAG review

https://github.com/w3ctag/design-reviews/issues/737

TAG review status

Pending

Risks

Interoperability and Compatibility

Gecko: No signal

WebKit: No signal

Web developers: No signals

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?

Debuggability

Basic support only.

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

No

Flag name

Requires code in //chrome?

False

Tracking bug

https://bugs.chromium.org/p/chromium/issues/detail?id=1323391

Estimated milestones

No milestones specified

Link to entry on the Chrome Platform Status

https://chromestatus.com/feature/5202879349522432

This intent message was generated by Chrome Platform Status.