Access to Promise.prototype.%somethingStandard% trigger promise/spec-only

[zloirock]

x:y  error  Avoid using non-standard 'Promise.prototype'  promise/spec-only

[voxpelli]

Why are you accessing Promise.prototype? 🤔

[zloirock]

It's a very strange question.

At first, because methods like .catch and .finally are generics and can be applied on non-native promises. At second, for caching for avoiding unneeded observable side effects, for preventing breakage in case of patching, etc. I have many other reasons to get access to methods from Promise.prototype.