[Home](./index.md) > [rc-js-util](./rc-js-util.md) > [ATypedArrayTuple](./rc-js-util.atypedarraytuple.md) > [copyWithin](./rc-js-util.atypedarraytuple.copywithin.md) ## ATypedArrayTuple.copyWithin() method Returns the this object after copying a section of the array identified by start and end to the same array starting at position target **Signature:** ```typescript copyWithin(_target: number, _start: number, _end?: number): this; ``` ## Parameters

Parameter	Type	Description
\_target	number	If target is negative, it is treated as length+target where length is the length of the array.
\_start	number	If start is negative, it is treated as length+start. If end is negative, it is treated as length+end.
\_end	number	_(Optional)_ If not specified, length of the this object is used as its default value.

**Returns:** this