Sounds like you needed Schema, which can ensure the shape and contents of a map as :pre and :post assertions in every function you annotate, then be turned off for production use.
https://github.com/Prismatic/schemaThat's why I come back to Clojure every time, if I need anything, it's available as a library. Need better typesafety? Just add in what you need with a macro or two. (Schema is not much more than that).
That's not really possible easily with Javascript, and Javascript has a lot more unsafe by default edge cases than Clojure. I'm not sure why if a mostly safe dynamic language bothers you, you'd now prefer an extremely unsafe dynamic language?
Lastly, types only give you a single dimension of safety, is this that exact shape, and ensuring I don't put a square peg into a round hole: both of which Schema adds in easily. Clojure is ALSO safe along many other dimensions, like thread saftey, immutably, null reference exceptions, etc.
