busterjs/buster

busterjs/referee: isPromise

mroderick opened this issue · 4 comments

mroderick commented

Is there any interest in a PR adding isPromise to busterjs/referee?

dkl-ppi commented

I am not sure. Do you think it is useful? Do you need it for testing?

dominykas commented

I'm not sure this would even be a good practice, e.g. there's no explicit instanceof assertion. Shouldn't you rather let the promise resolve/reject and check it that way?

Either way, what would the test for a promise be? There's a lot more to a promise than just then() and it's fairly easy to assert that then is a function. Is checking for anything more really possible, considering the plethora of promise libs and also the ES6 standard Promise?

dominykas commented

Just noticed that when calls this isPromiseLike and here's the check: https://github.com/cujojs/when/blob/ccd6970e55006abe73c110fe50eb315f3099bdf9/when.js#L161

mroderick commented

isPromiseLike would certainly work for the polyfilled scenarios.