Safari failing USE_NATIVE test for Promises

[Andarist]

https://github.com/zloirock/core-js/blob/master/modules/es6.promise.js#L23

Is this intended that Safari's native Promises failing this test? Does it mean that they are in some way buggy in Safari?

[Jessidhia]

Safari 9 doesn't support @@species, Safari 10 will pass it.

[Andarist]

I've encountered really weird bug when this polyfill Promise would not resolve cause of depending on MutationObserver and flush which runs queued microtasks was not called. Had that for quite some time during a debug, but later it got 'fixed' without me doing anything about it.

Maybe something has changed in the mean time, I dont know. Safari is a weird thing...

[zloirock]

Safari really fails some USE_NATIVE tests, you can check it. If you have an issue with MutationObserver - please, create a new issue and add a reproducible example.

[mvayngrib]

@Andarist @zloirock hit this issue as well, where in the console i'm typing Promise.resolve('hey').then(console.log) and it never resolves, the flush function never getting hit, while in the next tab it prints 'hey' like no one's business. Unfortunately i haven't figured out yet how to cause this issue on purpose.

OS: macOS sierra 10.12.1
Safari: Version 10.0.1 (12602.2.14.0.7)