Function langchainChatHistory

langchainChatHistory(
    mm: MemoryManager,
    ref: ConversationRef,
    opts?: { messageClasses?: LcMessageClasses },
): {
    getMessages(): Promise<LcChatMessage[]>;
    addMessage(message: LcChatMessage): Promise<void>;
    addMessages(messages: LcChatMessage[]): Promise<void>;
    clear(): Promise<void>;
}
LangChain.js: a governed BaseListChatMessageHistory implementation. Drop it in anywhere LangChain persists chat history (e.g. RunnableWithMessageHistory), getMessages reads the recent turns, and addMessage(s) pairs a human message with the following AI message into one governed turn (clear clears the session). Pass messageClasses to emit real HumanMessage/AIMessage instances (recommended for consumers that call BaseMessage methods); without it, structural { _getType, content } messages are returned (fine for reads). This returns a plain object that duck-types the interface: it is not a BaseListChatMessageHistory subclass, so passing it to APIs typed to BaseChatMessageHistory (e.g. RunnableWithMessageHistory) needs a cast: langchainChatHistory(...) as unknown as BaseChatMessageHistory.
```
import { HumanMessage, AIMessage } from "@langchain/core/messages";
const history = langchainChatHistory(mm, { agentId, sessionId }, { human: HumanMessage, ai: AIMessage });
```
Parameters
- mm: MemoryManager
- ref: ConversationRef
- opts: { messageClasses?: LcMessageClasses } = {}
Returns {
    getMessages(): Promise<LcChatMessage[]>;
    addMessage(message: LcChatMessage): Promise<void>;
    addMessages(messages: LcChatMessage[]): Promise<void>;
    clear(): Promise<void>;
}
- Defined in src/adapters.ts:426

Function langchainChatHistory

Parameters

Returns { getMessages(): Promise<LcChatMessage[]>; addMessage(message: LcChatMessage): Promise<void>; addMessages(messages: LcChatMessage[]): Promise<void>; clear(): Promise<void>;}

Settings

Returns {
getMessages(): Promise<LcChatMessage[]>;
addMessage(message: LcChatMessage): Promise<void>;
addMessages(messages: LcChatMessage[]): Promise<void>;
clear(): Promise<void>;
}