case-kata.clj

(def format-functions
  {:snake-case (fn [words]
                 (clojure.string/join "_" words))
   :kebab-case (fn [words]
                 (clojure.string/join "-" words))
   :camel-case (fn [words]
                 (apply str (first words)
                        (map clojure.string/capitalize (rest words))))
   :pascal-case (fn [words]
                  (apply str
                         (map clojure.string/capitalize words)))})

(defn extract-words [a-str]
  (map clojure.string/lower-case
       (filter #(not (#{"-" "_"} %))
               (re-seq #"[A-Z]?[a-z]+|-|_" a-str))))

(defn format [key _ to-format]
  (->
   key
   name
   extract-words
   ((to-format format-functions))
   keyword))

(clojure.test/deftest keyword-to-x-case-tests
  (clojure.test/are [x y] (= x y)
    (format :hello-koko :using :camel-case) :helloKoko
    (format :hello-koko :using :snake-case) :hello_koko
    (format :hello-koko :using :pascal-case) :HelloKoko
    (format :hello-koko :using :kebab-case) :hello-koko
    (format :helloKoko :using :kebab-case) :hello-koko))

(keyword-to-x-case-tests)