fgmccabe
commented
1 day ago As of https://chromium-review.googlesource.com/c/chromium/src/+/5922662, WPT tests for JSPI are in Chrome.
Open fgmccabe opened 2 weeks ago
fgmccabe
commented
1 day ago As of https://chromium-review.googlesource.com/c/chromium/src/+/5922662, WPT tests for JSPI are in Chrome.
Description
In order to support responsive applications written using WebAssembly it is necessary to provide functionality that allows WebAssembly programs to be suspended and resumed.The primary initial use case is to allow WebAssembly programs whose source relies on synchronous APIs to use asynchronous APIs that are increasingly common on the Web platform.The Promise integration proposal allows this to be done without changing the WebAssembly specification itself and without allowing JavaScript programs to be suspended (other than via existing async mechanisms).The feature is usable with any Promise-based JS or WebIDL API, but is especially useful for those targeted at high-performance applications, e.g. WebGPU. Interop 2024 proposal
In order to support responsive applications written using WebAssembly it is necessary to provide functionality that allows WebAssembly programs to be suspended and resumed.
The primary initial use case is to allow WebAssembly programs whose source relies on synchronous APIs to use asynchronous APIs that are increasingly common on the Web platform.
The Promise integration proposal allows this to be done without changing the WebAssembly specification itself and without allowing JavaScript programs to be suspended (other than via existing async mechanisms).
The feature is usable with any Promise-based JS or WebIDL API, but is especially useful for those targeted at high-performance applications, e.g. WebGPU.
Interop 2024 proposal
Specification
WebAssembly Phase 3 - https://github.com/WebAssembly/js-promise-integration
Additional Signals
Standards Positions
Mozilla - Positive https://github.com/mozilla/standards-positions/issues/944 WebKit - No information
Browser Bugs
Chromium Gecko
Tests
There is an active CL (https://chromium-review.googlesource.com/c/chromium/src/+/4908168) that will add JSPI tests to chromium and (by export) to wpt.fyi
Workarounds
The main work around is to use the binaryen ASYNCIFY feature. However, this can double the WebAssembly code size and cause a substantial reduction in performance (due to how ASYNCIFY works, the amount of code increase and performance cost varies depending on the complexity of the original source).