Some js frameworks require you to implement 'methods' and those methods need to access js this. Currelty this forces you to js*.
the following is handled by CLJS-83
Currently deftype only supports implementing protocol functions. It could be enhanced to support 'method' fns, possibly by using the Object section:
(deftype Foo [a]
(anyArbitraryMethod [a-name-for-this] ...))
Note that the arity of the actual fn would be one less than for protocol 'methods'.
Explore other options before going this way.
Supporting access to 'this' in stand-alone functions may cause gclosure to complain (it only wants to see traditional methods on prototypes), and is a non-objective for now.