The copyWithin method in JavaScript is used to copy a portion of an array to another location within the same array, without changing its length.
Note: This method modifies the original array and does not create a new one.
Syntax
array.copyWithin(target, start, end);target is the index to copy elements to, start is the index to begin copying from, and end (optional) is the index to stop copying (not inclusive).
Example
const array = [1, 2, 3, 4, 5];
array.copyWithin(0, 3);
console.log(array); // [4, 5, 3, 4, 5]