@langchain/langgraph
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JavaScript
import { END, START } from "../constants.js";
import { StateGraph } from "../graph/state.js";
import { ToolExecutor } from "./tool_executor.js";
import { RunnableLambda } from "@langchain/core/runnables";
import { FunctionMessage } from "@langchain/core/messages";
import { convertToOpenAIFunction } from "@langchain/core/utils/function_calling";
//#region src/prebuilt/chat_agent_executor.ts
/** @deprecated Use {@link createReactAgent} instead with tool calling. */
function createFunctionCallingExecutor({ model, tools }) {
let toolExecutor;
let toolClasses;
if (!Array.isArray(tools)) {
toolExecutor = tools;
toolClasses = tools.tools;
} else {
toolExecutor = new ToolExecutor({ tools });
toolClasses = tools;
}
if (!("bind" in model) || typeof model.bind !== "function") throw new Error("Model must be bindable");
const toolsAsOpenAIFunctions = toolClasses.map((tool) => convertToOpenAIFunction(tool));
const newModel = model.bind({ functions: toolsAsOpenAIFunctions });
const shouldContinue = (state) => {
const { messages } = state;
const lastMessage = messages[messages.length - 1];
if (!("function_call" in lastMessage.additional_kwargs) || !lastMessage.additional_kwargs.function_call) return "end";
return "continue";
};
const callModel = async (state, config) => {
const { messages } = state;
return { messages: [await newModel.invoke(messages, config)] };
};
const _getAction = (state) => {
const { messages } = state;
const lastMessage = messages[messages.length - 1];
if (!lastMessage) throw new Error("No messages found.");
if (!lastMessage.additional_kwargs.function_call) throw new Error("No function call found in message.");
return {
tool: lastMessage.additional_kwargs.function_call.name,
toolInput: JSON.stringify(lastMessage.additional_kwargs.function_call.arguments),
log: ""
};
};
const callTool = async (state, config) => {
const action = _getAction(state);
return { messages: [new FunctionMessage({
content: await toolExecutor.invoke(action, config),
name: action.tool
})] };
};
return new StateGraph({ channels: { messages: {
value: (x, y) => x.concat(y),
default: () => []
} } }).addNode("agent", new RunnableLambda({ func: callModel })).addNode("action", new RunnableLambda({ func: callTool })).addEdge(START, "agent").addConditionalEdges("agent", shouldContinue, {
continue: "action",
end: END
}).addEdge("action", "agent").compile();
}
//#endregion
export { createFunctionCallingExecutor };
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