A major limitation of using try/catch is that V8 will DEOPT your function call, which can be a 5-10x performance hit (to the current closure). The best way to avoid this is with a silly hack:

    function trycatchit(fn, that, args) {
      try {
        return fn.apply(that, args)
      } catch(e) {
       return e
      }
    }

    var value = trycatchit(fn, null, 'someValue')
    if (value instanceof Error) {
      ...
    }

Really though, you should just let co or whatever generator library you're using catch the error and rethrow it (or pass it to a callback) or be mindful to minimize your error handling.

[1] https://github.com/CrabDude/trycatch/blob/master/lib/trycatc...

That's not entirely true. If "db.insertUser()" is opening a database connection, who is going to close it on error?

The idea behind Zones for Node.js is to auto-attach new resources to the current zone, so that they can be cleaned when the zone exits.

AFAIK there is no solution for that at the moment.

I'm thinking whatever db plugin you're using, but also this pseudo code actually has a lot of implicit things going in the background (koa/co, thunks, etc).

It makes for some readable app code though.

have you tried Co (https://github.com/visionmedia/co) and if so what's your experience?