Promises and generators, you honestly lost me. Promises - where does this fit in in the whole? Generators - Yes I get that the generator iterates similar to a linked list in C++, but where does this fit in to Async matters?

I suspect what I wanted is a grander example showing how these work together in a coffeeshop or a post office to achieve whatever end they are ment to.

I think the reason I fail to user is how the moving parts fit together once in motion.