Function createIterator

lib/web/polyfill.js:494–497

(Constructor, NAME, next, proto)

  FF_ITERATOR in ArrayProto && hidden(O, FF_ITERATOR, value);
}
function createIterator(Constructor, NAME, next, proto){
  Constructor[PROTOTYPE] = create(proto || IteratorPrototype, {next: descriptor(1, next)});
  setToStringTag(Constructor, NAME + ' Iterator');
}
function defineIterator(Constructor, NAME, value, DEFAULT){
  var proto = Constructor[PROTOTYPE]
    , iter  = get(proto, SYMBOL_ITERATOR) || get(proto, FF_ITERATOR) || (DEFAULT && get(proto, DEFAULT)) || value;