[Home](./index.md) > [@apextoaster/js-utils](./js-utils.md) > [isNil](./js-utils.isnil.md) ## isNil() function Signature: ```typescript export declare function isNil(val: Optional): val is Nil; ``` ## Parameters | Parameter | Type | Description | | --- | --- | --- | | val | Optional<T> | | Returns: `val is Nil`