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[AI SDK](/c/ai-sdk/62)

# OnFinishResult Type

313 views · 5 likes · 4 posts


Ben (@frescoanalytics) · 2025-06-14 · ♥ 1

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I was looking at this part of the document on using onFinish callback.
https://ai-sdk.dev/docs/reference/ai-sdk-core/stream-text#on-finish
The document provides that the callback function take a parameter of OnFinishResult type. Can anyone please help me understand how to import this type? I'd be useful if I write the callback in other places than the inline function.

<!-- Current versus Expected behavior -->
Currently my IDE is suggesting type "any".


<!-- Code, configuration, and steps that reproduce this issue -->
```
async function onFinishCallback(result: any): Promise<void> {
    // This function is called when the AI has finished generating a response.
    console.log('\nAI response finished:', result);   
}
```
```
const result = streamText({
        model: google('gemini-2.5-flash-preview-05-20'),
        system: 'you are an assistant.',
        messages,
        providerOptions: /*something*/,
        onFinish: onFinishCallback,
    });
```

<!-- Project information (URL, framework, environment, project settings) -->


Ben (@frescoanalytics) · 2025-06-14 · ♥ 1

I found this line can be useful to define the type.
```
let onFinishResult: Parameters<
      Required<Parameters<typeof streamText>[0]>['onFinish']
    >[0];
```
https://github.com/vercel/ai/blame/26e70676e17e84a3e6d3054722365325a14cdc00/packages/ai/core/generate-text/stream-text.test.ts#L2315


BestCodes (@bestcodes) · 2025-06-14 · ♥ 1

Looks like you are right. I looked around in the codebase and didn't see any official `OnFinishResult` type (besides the type you mentioned used in testing). I might make a PR for this :smiley:


BestCodes (@bestcodes) · 2025-06-14 · ♥ 2

I did create a PR, but it's very small and maybe not necessary with the workarounds discussed here :smiling_face_with_tear: 
https://github.com/vercel/ai/pull/6749