copyWithin() method copies array elements
to another position in the array, overwriting the existing values.
This method will never add more items to the array.
target - The position where the copied element takes place.
start - It is optional. It represents the index from where the method starts copying elements. By default, it is 0.
end - It is optional. It represents the index at which elements stops copying. By default, it is array.length-1.