avoid error when sending the second message:TypeError: chatMessage._g…

…etType is not a function

pages/api/chat.ts

@@ -2,14 +2,27 @@ import type { NextApiRequest, NextApiResponse } from 'next';
 import { OpenAIEmbeddings } from 'langchain/embeddings/openai';
 import { Chroma } from 'langchain/vectorstores/chroma';
 import { makeChain } from '@/utils/makechain';
+import {BaseChatMessage, HumanChatMessage, AIChatMessage} from 'langchain/schema';
 
 export default async function handler(
   req: NextApiRequest,
   res: NextApiResponse,
 ) {
   const { question, history } = req.body;
 
-  console.log('question', question);
+  let histories: BaseChatMessage[] = [];
+  history.forEach(hist => {
+    if(hist['type'] === 'human')  {
+      let req: BaseChatMessage = new HumanChatMessage(question);
+      histories.push(req);
+    } else if (hist['type'] === 'ai') {
+      let respond: BaseChatMessage = new AIChatMessage(question);
+      histories.push(respond);
+    }
+  });
+
+
+  console.log('question:', question);
 
   //only accept post requests
   if (req.method !== 'POST') {
@@ -40,13 +53,13 @@ export default async function handler(
     //Ask a question using chat history
     const response = await chain.call({
       question: sanitizedQuestion,
-      chat_history: history || [],
+      chat_history: histories || [],
     });
 
     console.log('response', response);
     res.status(200).json(response);
   } catch (error: any) {
-    console.log('error', error);
+    console.log('error:', error);
     res.status(500).json({ error: error.message || 'Something went wrong' });
   }
 }

pages/index.tsx

@@ -6,6 +6,7 @@ import Image from 'next/image';
 import ReactMarkdown from 'react-markdown';
 import LoadingDots from '@/components/ui/LoadingDots';
 import { Document } from 'langchain/document';
+import {BaseChatMessage, HumanChatMessage, AIChatMessage} from 'langchain/schema';
 import {
   Accordion,
   AccordionContent,
@@ -20,7 +21,7 @@ export default function Home() {
   const [messageState, setMessageState] = useState<{
     messages: Message[];
     pending?: string;
-    history: [string, string][];
+    history: BaseChatMessage[];
     pendingSourceDocs?: Document[];
   }>({
     messages: [
@@ -81,6 +82,8 @@ export default function Home() {
       });
       const data = await response.json();
       console.log('data', data);
+      let req: BaseChatMessage = new HumanChatMessage(question);
+      let respond: BaseChatMessage = new AIChatMessage(data.text);
 
       if (data.error) {
         setError(data.error);
@@ -95,7 +98,7 @@ export default function Home() {
               sourceDocs: data.sourceDocuments,
             },
           ],
-          history: [...state.history, [question, data.text]],
+          history: [...state.history, req, respond],
         }));
       }
       console.log('messageState', messageState);

utils/makechain.ts

@@ -21,7 +21,8 @@ Helpful answer in markdown:`;
 export const makeChain = (vectorstore: Chroma) => {
   const model = new OpenAI({
     temperature: 0, // increase temepreature to get more creative answers
-    modelName: 'gpt-3.5-turbo', //change this to gpt-4 if you have access
+    modelName: 'gpt-3.5-turbo-0613', //change this to gpt-4 if you have access
+    //modelName: 'gpt-4', //change this to gpt-4 if you have access
   });
 
   const chain = ConversationalRetrievalQAChain.fromLLM(