[Home](./index.md) > [rc-js-util](./rc-js-util.md) > [arrayUnion](./rc-js-util.arrayunion.md) ## arrayUnion() function Given an `ArrayLike` of `ArrayLike`, provides all unique items in an `Array`. **Signature:** ```typescript export declare function arrayUnion(items: ArrayLike>, getComparisonValue?: (item: TItem, index: number) => unknown): TItem[]; ``` ## Parameters

Parameter	Type	Description
items	ArrayLike<ArrayLike<TItem>>
getComparisonValue	(item: TItem, index: number) => unknown	_(Optional)_

**Returns:** TItem\[\] ## Remarks See [arrayUnion()](./rc-js-util.arrayunion.md).