Web/JavaScript/Reference/Global objects/TypedArray/copyWithin

The copyWithin() method copies the sequence of array elements within the array to the position starting at target. The copy is taken from the index positions of the second and third arguments start and end. The end argument is optional and defaults to the length of the array. This method has the same algorithm as Array.prototype.copyWithin. TypedArray is one of the typed array types here.

Syntax

typedarray.copyWithin(target, start[, end = this.length])

Parameters

target: Target start index position where to copy the elements to.
start: Source start index position where to start copying elements from.
end Optional: Optional. Source end index position where to end copying elements from.

Return value

The modified array.

Description

See Array.prototype.copyWithin for more details.

Examples

Using copyWithin

var buffer = new ArrayBuffer(8);
var uint8 = new Uint8Array(buffer);
uint8.set([1,2,3]);
console.log(uint8); // Uint8Array [ 1, 2, 3, 0, 0, 0, 0, 0 ]
uint8.copyWithin(3,0,3);
console.log(uint8); // Uint8Array [ 1, 2, 3, 1, 2, 3, 0, 0 ]

Specifications

Specification
[(ECMA-262)The definition of 'TypedArray.prototype.copyWithin' in that specification.]

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
`copyWithin`	Chrome Full support 45	Edge Full support 14	Firefox Full support 34	IE No support No	Opera Full support 36	Safari Full support 9.1	WebView Android No support No	Chrome Android No support No	Firefox Android Full support 34	Opera Android No support No	Safari iOS Full support 9.3	Samsung Internet Android No support No	nodejs Full support 4.0.0

Legend

Full support: Full support
No support: No support