// Array :- It is collection more the single value inside an variable // keys(): This method creates and returns a new iterator object which holds the key for every index in the array. This method does not affect the original array. const arr1=[1,2,3,"m",89]; let r =arr1.keys(); for(let key of r){ console.log(key); //console.log(arr1[key] + " "+ "key"); } for(let key of r){//this loop is not executing console.log(arr1[key]); }