ClojureScript and JavaScript Comparison - ClojureScript Examples

cljs-and-js-comparision.cljs

;; Functions
(defn sum [x y] (+ x y))

;; Shorthand Functions
(def sum #(+ %1 %2))

;; Function Invocation
(sum 3 4)

;; Anonymous Functions
(fn [x y] (+ x y))

;; Anonymous Shorthand Functions
#(+ %1 %2)

;; map
(map inc [1 2 3])

;; filter
(filter odd? [1 2 3])

;; reduce
(reduce + 0 [1 2 3])

;; if without else
(when (= lang "de") "german")

;; if with else
(if (= lang "de")
  "german"
  "english")

;; if with multiple eles
(defn which-lang
  [lang]
  (cond
   (= lang "de") "german"
   (= lang "es") "spanish"
   :else "english"))

;; switch
(defn which-lang
  [lang]
  (case lang
    "de" "german"
    "es" "spanish"
    "english"))

;; falsy
false
nil

;; State
(atom {:one 1, :two 2})
(volatile! {:one 1, :two 2})

;; Interop
;; Method call
(.log js/console "Hello")

;; Property access
(.-PI js/Math)

;; Property setting
(set! (.-title js/document) "Hello")

;; window method call
(js/alert "Hello")

The which-lang cond example should be

(defn which-lang
  [lang]
  (cond
   (= lang "de") "german"
   (= lang "es") "spanish"
   :else "english"))

or, using condp,

(defn which-lang
  [lang]
  (condp = lang
   "de" "german"
   "es" "spanish"
   "english"))

Thank you @mfikes!