iterator.js

var Iterator = function(items) {
  this.index = 0;
  this.items = items;
}

Iterator.prototype = {
  first: () => {
      this.reset();
      return this.next();
  },
  next: () => {
      return this.items[this.index++];
  },
  hasNext: () => {
      return this.index <= this.items.length;
  },
  reset: () => {
      this.index = 0;
  },
  each: (callback) => {
      for (var item = this.first(); this.hasNext(); item = this.next()) {
          callback(item);
      }
  }
}
//--------------------

function run() {
  let items = [“one", 2, "circle", true, "Applepie"];
  let iter = new Iterator(items);

  // using for loop

  for (let item = iter.first(); iter.hasNext(); item = iter.next()) {
      //some action here
  }

  // using Iterator's each method
  iter.each((item) => {
      //some action here
  });
}