chore (ai): remove onResponse callback (#6281)

## Background

`onResponse` callback is unrelated to streaming and should not be used.

## Summary

Remove `onResponse` callback from `useChat` and `useCompletion`

Author: lgrammel

.changeset/heavy-ducks-join.md

@@ -0,0 +1,5 @@
+---
+'ai': major
+---
+
+chore (ai): remove onResponse callback

packages/ai/src/ui/call-chat-api.ts

@@ -24,7 +24,6 @@ export async function callChatApi<MESSAGE_METADATA>({
   credentials,
   headers,
   abortController,
-  onResponse,
   onUpdate,
   onFinish,
   onToolCall,
@@ -40,7 +39,6 @@ export async function callChatApi<MESSAGE_METADATA>({
   credentials: RequestCredentials | undefined;
   headers: HeadersInit | undefined;
   abortController: (() => AbortController | null) | undefined;
-  onResponse: ((response: Response) => void | Promise<void>) | undefined;
   onUpdate: (options: { message: UIMessage<MESSAGE_METADATA> }) => void;
   onFinish: UseChatOptions<MESSAGE_METADATA>['onFinish'];
   onToolCall: UseChatOptions<MESSAGE_METADATA>['onToolCall'];
@@ -72,10 +70,6 @@ export async function callChatApi<MESSAGE_METADATA>({
           credentials,
         });
 
-  if (onResponse != null) {
-    await onResponse(response);
-  }
-
   if (!response.ok) {
     throw new Error(
       (await response.text()) ?? 'Failed to fetch the chat response.',

packages/ai/src/ui/call-completion-api.ts

@@ -20,7 +20,6 @@ export async function callCompletionApi({
   setLoading,
   setError,
   setAbortController,
-  onResponse,
   onFinish,
   onError,
   fetch = getOriginalFetch(),
@@ -35,7 +34,6 @@ export async function callCompletionApi({
   setLoading: (loading: boolean) => void;
   setError: (error: Error | undefined) => void;
   setAbortController: (abortController: AbortController | null) => void;
-  onResponse: ((response: Response) => void | Promise<void>) | undefined;
   onFinish: ((prompt: string, completion: string) => void) | undefined;
   onError: ((error: Error) => void) | undefined;
   fetch: ReturnType<typeof getOriginalFetch> | undefined;
@@ -66,14 +64,6 @@ export async function callCompletionApi({
       throw err;
     });
 
-    if (onResponse) {
-      try {
-        await onResponse(response);
-      } catch (err) {
-        throw err;
-      }
-    }
-
     if (!response.ok) {
       throw new Error(
         (await response.text()) ?? 'Failed to fetch the chat response.',

packages/ai/src/ui/use-chat.ts

@@ -61,11 +61,6 @@ export type UseChatOptions<MESSAGE_METADATA = unknown> = {
     toolCall: ToolCall<string, unknown>;
   }) => void | Promise<unknown> | unknown;
 
-  /**
-   * Callback function to be called when the API response is received.
-   */
-  onResponse?: (response: Response) => void | Promise<void>;
-
   /**
    * Optional callback function that is called when the assistant message is finished streaming.
    *

packages/ai/src/ui/use-completion.ts

@@ -35,11 +35,6 @@ export type UseCompletionOptions = {
    */
   initialCompletion?: string;
 
-  /**
-   * Callback function to be called when the API response is received.
-   */
-  onResponse?: (response: Response) => void | Promise<void>;
-
   /**
    * Callback function to be called when the completion is finished streaming.
    */

packages/react/src/use-chat.ts

@@ -127,7 +127,6 @@ export function useChat<MESSAGE_METADATA>({
   experimental_prepareRequestBody,
   maxSteps = 1,
   streamProtocol = 'data',
-  onResponse,
   onFinish,
   onError,
   credentials,
@@ -256,7 +255,6 @@ Default is undefined, which disables throttling.
             ...chatRequest.headers,
           },
           abortController: () => abortControllerRef.current,
-          onResponse,
           onUpdate({ message }) {
             mutateStatus('streaming');
 
@@ -320,7 +318,6 @@ Default is undefined, which disables throttling.
       mutateStatus,
       api,
       extraMetadataRef,
-      onResponse,
       onFinish,
       onError,
       setError,

packages/react/src/use-completion.ts

@@ -71,7 +71,6 @@ export function useCompletion({
   body,
   streamProtocol = 'data',
   fetch,
-  onResponse,
   onFinish,
   onError,
   experimental_throttle: throttleWaitMs,
@@ -138,7 +137,6 @@ export function useCompletion({
         setLoading: mutateLoading,
         setError,
         setAbortController,
-        onResponse,
         onFinish,
         onError,
       }),
@@ -148,7 +146,6 @@ export function useCompletion({
       api,
       extraMetadataRef,
       setAbortController,
-      onResponse,
       onFinish,
       onError,
       setError,

packages/svelte/src/chat.svelte.ts

@@ -236,7 +236,6 @@ export class Chat<MESSAGE_METADATA = unknown> {
           ...chatRequest.headers,
         },
         abortController: () => abortController,
-        onResponse: this.#options.onResponse,
         onUpdate: ({ message }) => {
           this.#store.status = 'streaming';
 

packages/svelte/src/completion.svelte.ts

@@ -109,7 +109,6 @@ export class Completion {
       setAbortController: abortController => {
         this.#abortController = abortController ?? undefined;
       },
-      onResponse: this.#options.onResponse,
       onFinish: this.#options.onFinish,
       onError: this.#options.onError,
     });

packages/vue/src/use-chat.ts

@@ -106,7 +106,6 @@ export function useChat<MESSAGE_METADATA = unknown>(
     initialMessages = [],
     initialInput = '',
     streamProtocol = 'data',
-    onResponse,
     onFinish,
     onError,
     credentials,
@@ -207,7 +206,6 @@ export function useChat<MESSAGE_METADATA = unknown>(
         },
         abortController: () => abortController,
         credentials,
-        onResponse,
         onUpdate({ message }) {
           status.value = 'streaming';