## isDateString() function  
Returns true if the input value is a YYYY-MM-DD date string.

**Signature:**
```typescript
export declare function isDateString(input: unknown): input is string;
```

## Parameters  
| Parameter | Type    | Description                    |
| --------- | ------- | ------------------------------ |
| input     | unknown | Unknown input value.          |

**Returns:**
input is string

True if the input is a date string.

- [isDateString() function](/content/docs/sdk/core.isdatestring#isdatestring-function/index.html)
- [Parameters](/content/docs/sdk/core.isdatestring#parameters/index.html)