Simple Iterator

simpleIterator.js

function makeIterator(array) {
  var nextIndex = 0;
  console.log("nextIndex =>", nextIndex);

  return {
    next: function() {
      return nextIndex < array.length
        ? { value: array[nextIndex++], done: false }
        : { done: true };
    }
  };
}

var it = makeIterator(["simple", "iterator"]);

console.log(it.next()); // {value: 'simple, done: false}
console.log(it.next()); // {value: 'iterator, done: false}
console.log(it.next()); // {done: true}