refactor: replace message.content with message.parts (#868)

components/multimodal-input.tsx

@@ -1,11 +1,6 @@
 'use client';
 
-import type {
-  Attachment,
-  ChatRequestOptions,
-  CreateMessage,
-  Message,
-} from 'ai';
+import type { Attachment, Message } from 'ai';
 import cx from 'classnames';
 import type React from 'react';
 import {
@@ -21,8 +16,6 @@ import {
 import { toast } from 'sonner';
 import { useLocalStorage, useWindowSize } from 'usehooks-ts';
 
-import { sanitizeUIMessages } from '@/lib/utils';
-
 import { ArrowUpIcon, PaperclipIcon, StopIcon } from './icons';
 import { PreviewAttachment } from './preview-attachment';
 import { Button } from './ui/button';
@@ -324,7 +317,7 @@ function PureStopButton({
       onClick={(event) => {
         event.preventDefault();
         stop();
-        setMessages((messages) => sanitizeUIMessages(messages));
+        setMessages((messages) => messages);
       }}
     >
       <StopIcon size={14} />