# `StreamData`

<Note type="warning">

The `StreamData` class is deprecated and will be removed in a future version of AI SDK.
Please use `createDataStream`, `createDataStreamResponse`, and `pipeDataStreamToResponse` instead.

</Note>

The `StreamData` class allows you to stream additional data to the client (see [Streaming Data](/docs/ai-sdk-ui/streaming-data)).

## Import

### React

<Snippet text={`import { StreamData } from "ai"`} prompt={false} />

## API Signature

### Constructor

```ts
const data = new StreamData();
```

### Methods

#### `append`

Appends a value to the stream data.

```ts
data.append(value: JSONValue)
```

#### `appendMessageAnnotation`

Appends a message annotation to the stream data.

```ts
data.appendMessageAnnotation(annotation: JSONValue)
```

#### `close`

Closes the stream data.

```ts
data.close();
```


## Navigation

- [useChat](/v4/docs/reference/ai-sdk-ui/use-chat)
- [useCompletion](/v4/docs/reference/ai-sdk-ui/use-completion)
- [useObject](/v4/docs/reference/ai-sdk-ui/use-object)
- [useAssistant](/v4/docs/reference/ai-sdk-ui/use-assistant)
- [AssistantResponse](/v4/docs/reference/ai-sdk-ui/assistant-response)
- [convertToCoreMessages](/v4/docs/reference/ai-sdk-ui/convert-to-core-messages)
- [appendResponseMessages](/v4/docs/reference/ai-sdk-ui/append-response-messages)
- [appendClientMessage](/v4/docs/reference/ai-sdk-ui/append-client-message)
- [createDataStream](/v4/docs/reference/ai-sdk-ui/create-data-stream)
- [createDataStreamResponse](/v4/docs/reference/ai-sdk-ui/create-data-stream-response)
- [pipeDataStreamToResponse](/v4/docs/reference/ai-sdk-ui/pipe-data-stream-to-response)
- [StreamData](/v4/docs/reference/ai-sdk-ui/stream-data)


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