resend/fwd of accidental personal reply
Hello Medikoo, You seem to misunderstand what async functions do to be async. Your function has the same product as the following: new Promise((acc, rej) => acc(extendedPromise)) A promise that resolves to a extendedPromise instance. By no means do async functions use the returned values as their way of determining what type of promise they are: that'd break when using multiple returns with different types. I hope this explains it a bit for you. -Matthias On 14 Apr 2017 09:58, "medikoo" <[email protected]> wrote: While Promise methods and functions are friendly for it's extensions (or even not direct extensions but just thenables), the async function will always normalize it's result to instance of Promise, even it's ExtendedPromise, e.g.: class ExtendedPromise extends Promise {}; var extendedPromise = new ExtendedPromise(function (resolve) { resolve(); }); extendedPromise.then().constructor === ExtendedPromise // true var asyncFn = async function () { return extendedPromise; }; asyncFn().constructor === ExtendedPromise // false asyncFn().constructor === Promise // true That makes it cumbersome if we work with promise extensions. What was the reasoning behind such design? If not thenables in general, the promise extensions I believe should be passed through (or copied via its constructor.resolve). ------------------------------ View this message in context: Async functions not friendly to promise extensions <http://mozilla.6506.n7.nabble.com/Async-functions-not-friendly-to-promise-extensions-tp364921.html> Sent from the Mozilla - ECMAScript 4 discussion mailing list archive <http://mozilla.6506.n7.nabble.com/Mozilla-ECMAScript-4-discussion-f89340.html> at Nabble.com. _______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
_______________________________________________ es-discuss mailing list [email protected] https://mail.mozilla.org/listinfo/es-discuss
