变量 MessagesAnnotationConst

预置状态注解，用于组合返回的消息。可以处理标准消息和特殊修饰符，例如 RemoveMessage 实例。

具体来说，像这样导入和使用预置的 MessagesAnnotation

示例

import { MessagesAnnotation, StateGraph } from "@langchain/langgraph";

const graph = new StateGraph(MessagesAnnotation)
  .addNode(...)
  ...
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这相当于这样手动初始化您的状态

示例

import { BaseMessage } from "@langchain/core/messages";
import { Annotation, StateGraph, messagesStateReducer } from "@langchain/langgraph";

export const StateAnnotation = Annotation.Root({
  messages: Annotation<BaseMessage[]>({
    reducer: messagesStateReducer,
    default: () => [],
  }),
});

const graph = new StateGraph(StateAnnotation)
  .addNode(...)
  ...
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