Streaming does not function properly with withHistory and JsonOutputParser().

[yassinemellouki]

I use stream method of RunnableWithMessageHistory and JsonOutputParser for output. but I received this error

Error in handler RootListenersTracer, handleChainEnd: Error: Expected a string, BaseMessage, or array of BaseMessages. Received: undefined
and the history is not saved. the next invoke or stream does not taking into account the previous request (stream)

my code:

    const runnable = historyPrompt.pipe(this.LLM).pipe(new JsonOutputParser());

    const messageHistory = new ChatMessageHistory();

    const withHistory = new RunnableWithMessageHistory({
      runnable,
      getMessageHistory: () => {
        console.log('messageHistory', messageHistory);
        return messageHistory;
      },
      inputMessagesKey: 'input',
      historyMessagesKey: 'history',
    });

config:

    const config: RunnableConfig = {
      configurable: { sessionId: `text_${lang}_${Math.random() * 1000}_1` },
    };

stream:
withHistory.stream({ lang, input }, config);

[anglol]

Hi Yassine,

Did you find a solution to this problem ?

I have exactly the same using PostgresChatMessageHistory (supabase).