Smooth scroll Clojurescript example

smooth-scroll-clojurescript.cljs

(def speed 750)
(def moving-frequency 15)

(defn scroll-to-id
  [elem target-id]
  (let [target (.getElementById js/document target-id)
        elem-scroll-top (-> elem .-scrollTop)
        hop-count (/ speed moving-frequency)
        gap (/ (- (-> target .-offsetTop) elem-scroll-top) hop-count)]
    (doseq [i (range 1 (inc hop-count))]
      (let [move-to (+ elem-scroll-top (* gap i))
            timeout (* moving-frequency i)]
        (js/setTimeout #(set! (-> elem .-scrollTop) move-to) timeout)))))