my-update-in.clj

(defn my-update-in
  [m ks f & args]
  (assoc-in m ks (apply f (cons (get-in m ks) args))))

(comment
  (my-update-in {:author {:name "Dominik"}} [:author] vec)
  ;; => {:author [[:name "Dominik"]]}
  (my-update-in {:author {:name "Dominik"}} [:author :name] str " Magdalenski")
  ;; => {:author {:name "Dominik Magdalenski"}}
  (my-update-in {} [:author :name] str " Magdalenski")
  ;; => {:author {:name " Magdalenski"}}
)