protocolsince v0.0-927 clojure.lang/IndexedEdit
implemented for ArrayChunk BlackNode IndexedSeq IntegerRange IntegerRangeChunk MapEntry PersistentVector RedNode Subvec TransientVector

Source docstring:
Protocol for collections to provide indexed-based access to their items.
Source code @ clojurescript:src/main/cljs/cljs/core.cljs
(defprotocol IIndexed
  (-nth [coll n] [coll n not-found]
    "Returns the value at the index n in the collection coll.
     Returns not-found if index n is out of bounds and not-found is supplied."))