arrayFuncKeys.js

"use strict";

var log = function log(x) {
  console.log(x);
};

var ary = [10, 23, 4, 0, 77];

var s = ary.keys();
log(s.next()); // {"value":0,"done":false}
log(s.next()); // {"value":1,"done":false}
log(s.next()); // {"value":2,"done":false}
log(s.next()); // {"value":3,"done":false}
log(s.next()); // {"value":4,"done":false}
log(s.next()); // {"done":true}