## isString() function [​](/content/docs/sdk/core.isstring#isstring-function "Direct link to isString(/index.html) function")

Returns true if the input value is a string.

**Signature:**

```typescript
export declare function isString(value: unknown): value is string;
```

## Parameters [​](/content/docs/sdk/core.isstring#parameters "Direct link to Parameters"/index.html)

| Parameter | Type    | Description             |
| --------- | ------- | ----------------------- |
| value     | unknown | The candidate value.    |

**Returns:**

value is string

True if the input value is a string.

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