Intent to ship: WebAssembly JS-Promise-Integration

[Ryan Hunt]

As of Fx153 I intend to enable WebAssembly JS-Promise-Integration (JSPI)

by default on all platforms.

WebAssembly JS-Promise-Integration allows synchronous WebAssembly code

to call asynchronous Web APIs. It does this by suspending the synchronous

WebAssembly execution stack and yielding a new promise that awaits the result

of the Web API's promise. When that promise resolves, WebAssembly execution is

resumed with the result.

This feature has been developed and shipped behind a pref, enabled Nightly-only

since Fx152. We saw no major regressions, so I now intend to turn it on by

default on all channels.

Intent to prototype thread:

https://groups.google.com/a/mozilla.org/g/dev-platform/c/r0JfIYxym6Q

Bug to turn on by default:

https://bugzilla.mozilla.org/show_bug.cgi?id=2044809

Specification:

https://github.com/WebAssembly/js-promise-integration

This is a Phase 4 WebAssembly proposal. It is finished but has not yet been

merged into the official spec document.

Standards body:

W3C (WebAssembly CG & WG)

Platform coverage:

All.

Preference:

javascript.options.wasm_js_promise_integration

DevTools bug:

https://bugzilla.mozilla.org/show_bug.cgi?id=2036877

Extensions bug:

N/A

Use counter:

N/A

W3C Tag review:

https://github.com/w3ctag/design-reviews/issues/809

Standards-positions discussion:

https://github.com/mozilla/standards-positions/issues/944

Other browsers:

- Blink: Shipped / Positive

https://chromestatus.com/feature/5674874568704000

- WebKit: Shipping, with a neutral standards-position

Standards-position: https://github.com/WebKit/standards-positions/issues/422

In Safari 27 beta: https://webkit.org/blog/17967/news-from-wwdc26-webkit-in-safari-27-beta/

web-platform-tests:

https://wpt.fyi/results/wasm/jsapi/jspi?label=master&label=experimental&aligned&q=wasm%2Fjsapi%2Fjspi