JavaScript Array copyWithin()

Copy to index 2, all elements from index 0:

const fruits = ["Banana", "Orange", "Apple", "Mango"];
fruits.copyWithin(2, 0);

Copy to index 2, the elements from index 0 to 2:

const fruits = ["Banana", "Orange", "Apple", "Mango", "Kiwi"];
fruits.copyWithin(2, 0, 2);

Description

The copyWithin() method copies array elements to another position in an array.

The copyWithin() method overwrites the existing values.

The copyWithin() method does not add items to the array.

array.copyWithin(target, start, end)

Parameter	Description
target	Required. The index (position) to copy the elements to.
start	Optional. The start index (position). Default is 0.
end	Optional. The end index (position). Default is the array length.

Type	Description
Array	The changed array.

copyWithin() is an ECMAScript6 (ES6) feature.

ES6 (JavaScript 2015) is supported in all modern browsers since June 2017:


Chrome 51	Edge 15	Firefox 54	Safari 10	Opera 38
May 2016	Apr 2017	Jun 2017	Sep 2016	Jun 2016

copyWithin() is not supported in Internet Explorer.