@langgraph-js/pro/dist/createModelHelper.js

The Pro SDK for LangGraph - seamlessly integrate your AI agents with frontend interfaces and build complex AI workflows

import { createDefaultAnnotation, createState } from "./createState.js";
import { ChatOpenAI } from "@langchain/openai";
/**
 * 创建模型状态和模型工具
 * @param ModelAllow 模型允许值的定义，可以传入，第一个为默认值
 * @returns 模型状态和模型工具
 * @example
 * const { ModelState, createLLM } = createModelHelper({
 *     main_model: ["gemini-2.5-flash"],
 * });
 * const GraphState = createState(ModelState).build({});
 * const llm = await createLLM(state, "main_model");
 */
export const createModelHelper = (ModelAllow) => {
    const ModelState = createState().build({
        ...Object.fromEntries(Object.entries(ModelAllow).map(([key, value]) => [key, createDefaultAnnotation(() => value[0])])),
    });
    const modelGuard = (state, model_type) => {
        const modelName = state[model_type];
        if (!modelName) {
            throw new Error(`Model ${String(model_type)} not found in state`);
        }
        if (!ModelAllow[model_type].includes(modelName)) {
            throw new Error(`Not Allowed Model ${String(model_type)} `);
        }
        return modelName;
    };
    async function createLLM(state, model_type, params = {}) {
        const modelName = modelGuard(state, model_type);
        return new ChatOpenAI({
            modelName,
            ...params,
            configuration: {
                /** @ts-ignore */
                parallel_tool_calls: true,
            },
            streamUsage: true,
            streaming: true,
        });
    }
    return {
        ModelState,
        createLLM,
    };
};