fix: set content before sending to provider

Author: bfischer1121

app/(chat)/chat/[id]/page.tsx

@@ -35,12 +35,18 @@ export default async function Page(props: { params: Promise<{ id: string }> }) {
   });
 
   function convertToUIMessages(messages: Array<DBMessage>): Array<UIMessage> {
+    const textFromParts = (message.parts as UIMessage['parts'])
+      .filter((part) => part.type === 'text')
+      .map((part) => part.text)
+      .join('\n')
+      .trim();
+
     return messages.map((message) => ({
       id: message.id,
       parts: message.parts as UIMessage['parts'],
       role: message.role as UIMessage['role'],
       // Note: content will soon be deprecated in @ai-sdk/react
-      content: '',
+      content: textFromParts,
       createdAt: message.createdAt,
       experimental_attachments:
         (message.attachments as Array<Attachment>) ?? [],