I have nothing against Coffeescript, but its future as a language has been debated as of late (due to ES6, ES7, babel, etc)... I have ported the cql-execution engine (and all tests) to ES6, which even with decaffeinate was more work than one might think! Not sure if you are interested, but I am willing to contribute it if you want it.. If not, no big deal, just thought I would offer it up... I currently have it in a private repo, but will open it up if there is any interest. Cheers!

Jeff