This looks pretty cool, but it seems to me it has hardly more than a sprinkling of "functional taste". Promises are much more functional in the modern sense of

This looks pretty cool, but it seems to me it has hardly more than a sprinkling of "functional taste". Promises are much more functional in the modern sense of preserving composability outside the abstraction by creating values that represent asynchronous computations, which can be composed flexibly with a then method.