I know that you can use the following types to extend
object, array, function, string, nil
i.e.
(extend-type nil Functor
(fmap
([_ _] nil)
([_ _ _] nil)))
I'm hoping to do the same for the native date object. how is that done?
also.. are there anymore lowercase types that I'm missing?
Here is how to extend Date object:
(defprotocol Functor
(fmap [_]))
(extend-type js/Date
Functor
(fmap
([_] (.log js/console 42))))
(fmap (js/Date.)) ;; logs 42
A list of lowercase types (from https://github.com/clojure/clojurescript/blob/202cfcf045cf86d3ab295cbf16a347569b652647/src/cljs/clojure/data.cljs):
nil, string, number, array, function, boolean, default
From himera (http://himera.herokuapp.com/synonym.html):
;; In addition native JavaScript objects like
;; Function, Object, Array, Number, String
;; are never actually directly extended
;; For example say you'd like to use RegExps
;; as functions
(extend-type js/RegExp
IFn
(-invoke
([this s]
(re-matches this s))))
(filter #"foo.*" ["foo" "bar" "foobar"])
;; => ("foo" "foobar")
;; This is precisely how callable collections
;; are implemented.
