ibm-cloud-sdk-core/build/docs/ibm-cloud-sdk-core.onlyone.md

Core functionality to support SDKs generated with IBM's OpenAPI SDK Generator.

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## onlyOne() function

Checks that exactly one of the arguments provided is defined. Returns true if one argument is defined. Returns false if no argument are defined or if 2 or more are defined.

**Signature:**

```typescript
export declare function onlyOne(...args: any): boolean;
```

## Parameters

<table><thead><tr><th>

Parameter


</th><th>

Type


</th><th>

Description


</th></tr></thead>
<tbody><tr><td>

args


</td><td>

any


</td><td>

The spread of arguments to check


</td></tr>
</tbody></table>
**Returns:**

boolean

true if and only if exactly one argument is defined