is-actual-promise

Similar to p-is-promise and
is-promise, which are also both
fine alternatives to this.

Differences (ie, "why this thing then?")

* This module is hybrid, so it can be used in either commonjs or
esm. is-promise is hybrid, but p-is-promise is ESM-only.
* This module asserts that the tested value supplies the full
actual Promise interface, not just PromiseLike (ie, it also
asserts .catch() and .finally(). (p-is-promise tests for
.catch(), neither tests for .finally().)
* This module provides a named export rather than a default
export, which is a bit less of a hassle in some scenarios.
* This module does not verify the resolution type of the Promise,
since that cannot be determined or verified, only that it's a
Promise.

(Note that this module does _not_ verify that the .catch(),
.then(), and .finally() methods return Promises, because that
is impossible at run-time without actually calling them. No
duck-typing method should ever be considered fully
authoritative.)

USAGE

``ts
import { isPromise } from 'is-actual-promise'

console.log(isPromise(new Promise(() => {}))) // true
console.log(isPromise((async () => true)())) // true
console.log(isPromise(Promise.resolve(true))) // true
console.log(isPromise({
then: async () => 5,
finally: async () => {},
catch: () => {},
})) // true, but not accurate, limitation of duck typing
``