JavaScript Array copyWithin() method

The JavaScript array copyWithin() method copies the part of the given array with its own elements and returns the modified array. This method doesn't change the length of the modified array.

Syntax

The copyWithin() method is represented by the following syntax:

Parameter

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.

Return

The modified array.

JavaScript Array copyWithin() method example

Let's see some examples of copyWithin() method.

Example 1

Here, we will pass the target, start and end index with the method.

<script>
var arr=["AngularJS","Node.js","JQuery","Bootstrap"]
// place at 0th position, the element between 1st and 2nd position.
var result=arr.copyWithin(0,1,2);
document.writeln(result);
</script>

Test it Now

Output:

Node.js,Node.js,JQuery,Bootstrap

Example 2

Let's see one more example where we will copy two elements.

</script>
var arr=["AngularJS","Node.js","JQuery","Bootstrap"]
// place from 0th position, the elements between 1st and 3rd position.
var result=arr.copyWithin(0,1,3);
document.writeln(result);
</script>

Test it Now

Output:

Node.js,JQuery,JQuery,Bootstrap

Example 3

In this example, we will provide only the target index and start index.

<script>
var arr=["AngularJS","Node.js","JQuery","Bootstrap"];
// place from 1st position, the elements after 2nd position.
var result=arr.copyWithin(1,2);
document.writeln(result);
</script>

Test it Now

Output:

AngularJS,JQuery,Bootstrap,Bootstrap

Example 4

In this example, we will provide target index only.

<script>
var arr=["AngularJS","Node.js","JQuery","Bootstrap"];
// place from 2nd position, the elements after 0th position.
var result=arr.copyWithin(2);
document.writeln(result);
</script>

Test it Now

Output: