TypedArray.prototype.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.

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Syntax

copyWithin(target, start)
copyWithin(target, start, end)

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

const buffer = new ArrayBuffer(8);
const 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
ECMAScript Language Specification
# sec-%typedarray%.prototype.copywithin

Browser compatibility

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See also