We intend to implement and ship Promise.any, a proposed way to `await` several promises and continue as soon as any of them becomes fulfilled. André Bargull [:anba] has contributed patches implementing this feature. It will land in Nightly soon.
We'll ship it once we're confident the specification is stable (Promise.any is at Stage 3 in the TC39 Process[1], but some minor changes are still in flight). Bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1568903 Proposed standard: https://tc39.es/proposal-promise-any/ Proposal repository: https://github.com/tc39/proposal-promise-any/ MDN: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/any Platform coverage: All, Nightly only, no pref DevTools bug: N/A Other browsers: Not implementing yet, as far as I can tell. I expect V8 will start soon and JSC will implement it eventually. Polyfills are already available for this proposal[2][3]. Testing: The patch[4] contains tests, including tests for aspects of behavior that we do not expect test262 to test thoroughly: error stacks and cross-realm behavior. Test262 will eventually provide independent tests. Use cases: Promise.any is similar to Promise.race. It's for cases in async code when you would use Promise.race, but you're interested in the first success, not the first failure. If you were implementing something like Gecko's "Race Cache With Network" behavior[5][6], you might write: ```js let response = await Promise.any([network_fetch, cache_fetch]); ``` [1]: https://tc39.es/process-document/ [2]: https://github.com/zloirock/core-js#promiseany [3]: https://github.com/es-shims/Promise.any#promiseany- [4]: https://phabricator.services.mozilla.com/D51659 [5]: https://groups.google.com/forum/#!topic/mozilla.dev.platform/fvCmc6kR9Uk [6]: about:networking#rcwn -j _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
