functionsince v0.0-927 clojure.core/isa?Edit
(isa? child parent)
(isa? h child parent)

See Also:

Source docstring:
Returns true if (= child parent), or child is directly or indirectly derived from
parent, either via a JavaScript type inheritance relationship or a
relationship established via derive. h must be a hierarchy obtained
from make-hierarchy, if not supplied defaults to the global
Source code @ clojurescript:src/main/cljs/cljs/core.cljs
(defn ^boolean isa?
  ([child parent] (isa? @(get-global-hierarchy) child parent))
  ([h child parent]
     (or (= child parent)
         ;; (and (class? parent) (class? child)
         ;;    (. ^Class parent isAssignableFrom child))
         (contains? ((:ancestors h) child) parent)
         ;;(and (class? child) (some #(contains? ((:ancestors h) %) parent) (supers child)))
         (and (vector? parent) (vector? child)
              (== (count parent) (count child))
              (loop [ret true i 0]
                (if (or (not ret) (== i (count parent)))
                  (recur (isa? h (child i) (parent i)) (inc i))))))))