> ## Documentation Index
> Fetch the complete documentation index at: https://docs.devin.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# isExtension

```typescript
isExtension(notification: CognitionExtensionNotification, method: M): notification
```

Narrow a [CognitionExtensionNotification](https://docs.devin.ai/sdk/reference/types/CognitionExtensionNotification.md) to a specific typed
notification by its method. Needed (instead of comparing `method` inline)
because [UnknownExtensionNotification](https://docs.devin.ai/sdk/reference/interfaces/UnknownExtensionNotification.md) carries a plain-`string`
method, which defeats discriminated-union narrowing.

## Parameters

**notification** `CognitionExtensionNotification` *required*

**method** `M` *required*

## Returns

`notification`


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