iterator.js

function iterator(arr){

    var id = setInterval(

      function(){
        console.log('haha')
        if(arr.length > 0){
          console.log(arr.shift())
        }else{
          clearInterval(id)
        }
      }, 1000)
}


function iteratorManually(arr){

  return function(){
  //console.log('haha')
    if(arr.length > 0){
      console.log(arr.pop())
   }
  }
}