langchain.js
    Preparing search index...

    Class BufferWindowMemory

    Class for managing and storing previous chat messages. It extends the BaseChatMemory class and implements the BufferWindowMemoryInput interface. This class is stateful and stores messages in a buffer. When called in a chain, it returns all of the messages it has stored.

    const prompt =
      PromptTemplate.fromTemplate(`The following is a friendly conversation between a human and an AI. The AI is talkative and provides lots of specific details from its context. If the AI does not know the answer to a question, it truthfully says it does not know.
    Current conversation:
    {chat_history}
    Human: {input}
    AI:`);

    const chain = new LLMChain({
      llm: new ChatOpenAI({ model: "gpt-4o-mini", temperature: 0.9 }),
      prompt,
      memory: new BufferWindowMemory({ memoryKey: "chat_history", k: 1 }),
    });

    // Example of initiating a conversation with the AI
    const res1 = await chain.call({ input: "Hi! I'm Jim." });
    console.log({ res1 });

    // Example of following up with another question
    const res2 = await chain.call({ input: "What's my name?" });
    console.log({ res2 });

    Hierarchy (View Summary)

    Implements

    Index

    Constructors

    constructor

    Properties

    aiPrefix chatHistory humanPrefix inputKey? k memoryKey outputKey? returnMessages

    Accessors

    memoryKeys

    Methods

    clear loadMemoryVariables saveContext

    Constructors

    Properties

    aiPrefix: string = "AI"
    chatHistory: BaseChatMessageHistory
    humanPrefix: string = "Human"
    inputKey?: string
    k: number = 5
    memoryKey: string = "history"
    outputKey?: string
    returnMessages: boolean = false

    Accessors

    • get memoryKeys(): string[]

      Returns string[]

    Methods

    • Method to clear the chat history.

      Returns Promise<void>

      Promise that resolves when the chat history has been cleared.

    • Method to load the memory variables. Retrieves the chat messages from the history, slices the last 'k' messages, and stores them in the memory under the memoryKey. If the returnMessages property is set to true, the method returns the messages as they are. Otherwise, it returns a string representation of the messages.

      Parameters

      • _values: InputValues

        InputValues object.

      Returns Promise<MemoryVariables>

      Promise that resolves to a MemoryVariables object.

    • Method to add user and AI messages to the chat history in sequence.

      Parameters

      • inputValues: InputValues

        The input values from the user.

      • outputValues: OutputValues

        The output values from the AI.

      Returns Promise<void>

      Promise that resolves when the context has been saved.

    Settings

    Member Visibility

    On This Page

    Constructors
    Properties
    Accessors
    Methods