[Home](./index.md) > [@apextoaster/js-utils](./js-utils.md) > [doesExist](./js-utils.doesexist.md) ## doesExist() function Check if a variable is not nil. Signature: ```typescript export declare function doesExist(val: Optional): val is T; ``` ## Parameters | Parameter | Type | Description | | --- | --- | --- | | val | [Optional](./js-utils.optional.md)<T> | | Returns: val is T