Promises and generators actually work magnificently well together. I would recomend taking a look at an implementation of Task.js [1] [2] and, for example, some of its (increasing) usage across the Mozilla codebase [3].

[1] https://github.com/mozilla/mozilla-central/blob/master/toolk...

[2] https://developer.mozilla.org/en-US/docs/Mozilla/JavaScript_...

[3] http://dxr.mozilla.org/mozilla-central/search?tree=mozilla-c...