- **Description**

Creates a validator which succeedes when value is empty.

- *Notes*:
  - Value is empty when `value.length === 0`
  - This validator requires value to be defined:

- **How to import**

```typescript
import { empty } from 'pipedator';
// or
import { empty } from 'pipedator/lib/empty';

```
- **Signature**

```typescript
function empty<ValidValue = any>(message?: string): Validator<ValidValue>;
```
- **Parameters**
  - `message` - (optional) custom message.


- **Usage**

```typescript
const validator = empty();

validator.validate(''); // valid
validator.validate('not empty string'); // invalid
validator.validate([]); // valid
validator.validate([1]); // invalid
validator.validate({ length: 0 }); // valid
validator.validate(null); // throws an error (trying to read property length from null)
validator.validate(undefined); // throws an error (trying to read property length from undefined)
```