js-on-sx: instanceof accepts function operands (fn instanceof Function/Object)

lib/js/runtime.sx

@@ -769,9 +769,20 @@
   (fn
     (obj ctor)
     (cond
-      ((not (= (type-of obj) "dict")) false)
       ((not (js-function? ctor))
         (error "TypeError: Right-hand side of instanceof is not callable"))
+      ((js-function? obj)
+        (let
+          ((proto (js-get-ctor-proto ctor))
+            (fnproto (get js-function-global "prototype"))
+            (objproto (get Object "prototype")))
+          (cond
+            ((= proto fnproto) true)
+            ((= proto objproto) true)
+            ((and (= (type-of obj) "dict") (contains? (keys obj) "__proto__"))
+              (js-instanceof-walk obj proto))
+            (else false))))
+      ((not (= (type-of obj) "dict")) false)
       (else
         (let
           ((proto (js-get-ctor-proto ctor)))