[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`