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.

This method replaces the experimental TypedArray.prototype.move().

Examples

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	Status	Comment
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'TypedArray.prototype.copyWithin' in that specification.	Standard	Initial definition.
ECMAScript 2017 Draft (ECMA-262) The definition of 'TypedArray.prototype.copyWithin' in that specification.	Draft

Browser compatibility

See also

• TypedArray