There exist nice lib for Erlang-style pattern-matching in JS – matches.js ( https://github.com/natefaubion/matches.js).
I‘ve prepared gist http://bit.ly/1QqQy4w, that contains bit extended and modified matches.js, see comment under the gist. In short: now ready for ddocs (knows about CouchDB require) and supports recursive syntax. See comment under the gist and original matches.js docs. Note, that compilation of matcher is not lazy, but it‘s nearly indistinguishable comparing to other penalties of typical JS-backed request in CouchDB. Good for new js rewrites (routing) and for (validate_doc_)update update functions (type check). ermouth
