// Array :- It is collection more the single value inside an variable // copywithin -It copies the element from the own array and return to new array // array.copyWithin(target, start, end) // target - position where the copied element take place // Start :- from which index it is gonna start the copying // end : before the specified index var arr=["AngularJS","Node.js","JQuery","Bootstrap" , 89] // place from 0th position, the elements between 1st and 3rd position. console.log(arr); var result=arr.copyWithin(0,1,3); //here the replacement not happen till the thired index it will end before it //and also will keep repeating the second last index until it reaches the final array length console.log(result);