[Proposal] fix: use friendlier promise checking

[swain]

Motivation

The current syntax is not friendly to scenarios where the global Promise object may have been re-mapped to a different class, and async functions are being used. Example:

class WrappedPromise {
  // ...
}

global.Promise = WrappedPromise;

const asyncFunction = async () => 'something';

const result = asyncFunction();

console.log(result instanceof Promise);

This syntax should be more resilient against weird Promise scenarios, including this one.

[swain]

@fengmk2 would love any feedback on this PR

[swain]

@fengmk2 bumping this PR :)

[fengmk2]

@smolster Can you add a test case to cover this change?

[fengmk2]

origin could be a normal function, why we need to change it to a promise?

[swain]

I think you're asking "why would we use Promise.resolve().then(...)" instead of just using await options.origin(ctx). I updated to use that simpler syntax.

If that's not what you're asking, could you elaborate a little more on your question?

[swain]

@fengmk2 tests added 👍🏻 -- apologies for leaving it off at first.

[swain]

@fengmk2 bumping this fix

[swain]

@fengmk2 any update on this PR?

[swain]

@fengmk2 coming up on 2 months since this PR has been opened. Is it safe to merge now?

[swain]

@fengmk2 3 months since this PR opened :/ -- think we can merge it?

[fengmk2]

@swain I will add more tests before npm publish.

[fengmk2]

3.4.0