使用 nodeJS 从头开始​​创建 ReAct Agent（维基百科搜索）

mkdir react-agent-project
cd react-agent-project
npm init -y
npm install axios dotenv @google/generative-ai

google_ai_api_key=your_api_key_here

const axios = require("axios");

class tools {
  static async wikipedia(q) {
    try {
      const response = await axios.get("https://en.wikipedia.org/w/api.php", {
        params: {
          action: "query",
          list: "search",
          srsearch: q,
          srwhat: "text",
          format: "json",
          srlimit: 4,
        },
      });

      const results = await promise.all(
        response.data.query.search.map(async (searchresult) => {
          const sectionresponse = await axios.get(
            "https://en.wikipedia.org/w/api.php",
            {
              params: {
                action: "parse",
                pageid: searchresult.pageid,
                prop: "sections",
                format: "json",
              },
            },
          );

          const sections = object.values(
            sectionresponse.data.parse.sections,
          ).map((section) => `${section.index}, ${section.line}`);

          return {
            pagetitle: searchresult.title,
            snippet: searchresult.snippet,
            pageid: searchresult.pageid,
            sections: sections,
          };
        }),
      );

      return results
        .map(
          (result) =>
            `snippet: ${result.snippet}\npageid: ${result.pageid}\nsections: ${json.stringify(result.sections)}`,
        )
        .join("\n\n");
    } catch (error) {
      console.error("error fetching from wikipedia:", error);
      return "error fetching data from wikipedia";
    }
  }

  static async wikipedia_with_pageid(pageid, sectionid) {
    if (sectionid) {
      const response = await axios.get("https://en.wikipedia.org/w/api.php", {
        params: {
          action: "parse",
          format: "json",
          pageid: parseint(pageid),
          prop: "wikitext",
          section: parseint(sectionid),
          disabletoc: 1,
        },
      });
      return object.values(response.data.parse?.wikitext ?? {})[0]?.substring(
        0,
        25000,
      );
    } else {
      const response = await axios.get("https://en.wikipedia.org/w/api.php", {
        params: {
          action: "query",
          pageids: parseint(pageid),
          prop: "extracts",
          exintro: true,
          explaintext: true,
          format: "json",
        },
      });
      return object.values(response.data?.query.pages)[0]?.extract;
    }
  }
}

module.exports = tools;

require("dotenv").config();
const { googlegenerativeai } = require("@google/generative-ai");
const tools = require("./tools");

const genai = new googlegenerativeai(process.env.google_ai_api_key);

class reactagent {
  constructor(query, functions) {
    this.query = query;
    this.functions = new set(functions);
    this.state = "thought";
    this._history = [];
    this.model = genai.getgenerativemodel({
      model: "gemini-1.5-flash",
      temperature: 2,
    });
  }

  get history() {
    return this._history;
  }

  pushhistory(value) {
    this._history.push(`\n ${value}`);
  }

  async run() {
    this.pushhistory(`**task: ${this.query} **`);
    try {
      return await this.step();
    } catch (e) {
      if (e.message.includes("exhausted")) {
        return "sorry, i'm exhausted, i can't process your request anymore. ><";
      }
      return "unable to process your request, please try again? ><";
    }
  }

  async step() {
    const colors = {
      reset: "\x1b[0m",
      yellow: "\x1b[33m",
      red: "\x1b[31m",
      cyan: "\x1b[36m",
    };

    console.log("====================================");
    console.log(
      `next movement: ${
        this.state === "thought"
          ? colors.yellow
          : this.state === "action"
            ? colors.red
            : this.state === "answer"
              ? colors.cyan
              : colors.reset
      }${this.state}${colors.reset}`,
    );
    console.log(`last movement: ${this.history[this.history.length - 1]}`);
    console.log("====================================");
    switch (this.state) {
      case "thought":
        await this.thought();
        break;
      case "action":
        await this.action();
        break;
      case "answer":
        await this.answer();
        break;
    }
  }

  async promptmodel(prompt) {
    const result = await this.model.generatecontent(prompt);
    const response = await result.response;
    return response.text();
  }

  async thought() {
    const availablefunctions = json.stringify(array.from(this.functions));
    const historycontext = this.history.join("\n");
    const prompt = `your task to fullfill ${this.query}.
context contains all the reflection you made so far and the actionresult you collected.
availableactions are functions you can call whenever you need more data.

context: "${historycontext}" <<

availableactions: "${availablefunctions}" <<

task: "${this.query}" <<

reflect uppon your task using context, actionresult and availableactions to find your next_step.
print your next_step with a thought or fullfill your task `;

    const thought = await this.promptmodel(prompt);
    this.pushhistory(`\n **${thought.trim()}**`);
    if (
      thought.tolowercase().includes("fullfill") ||
      thought.tolowercase().includes("fulfill")
    ) {
      this.state = "answer";
      return await this.step();
    }
    this.state = "action";
    return await this.step();
  }

  async action() {
    const action = await this.decideaction();
    this.pushhistory(`** action: ${action} **`);
    const result = await this.executefunctioncall(action);
    this.pushhistory(`** actionresult: ${result} **`);
    this.state = "thought";
    return await this.step();
  }

  async decideaction() {
    const availablefunctions = json.stringify(array.from(this.functions));
    const historycontext = this.history;
    const prompt = `reflect uppon the thought, query and availableactions

    ${historycontext[historycontext.length - 2]}

    thought <<< ${historycontext[historycontext.length - 1]}

    query: "${this.query}"

    availableactions: ${availablefunctions}

    output only the function,parametervalues separated by a comma. for example: "wikipedia,ronaldinho gaucho, 1450"`;

    const decision = await this.promptmodel(prompt);
    return `${decision.replace(/`/g, "").trim()}`;
  }

  async executefunctioncall(functioncall) {
    const [functionname, ...args] = functioncall.split(",");
    const func = tools[functionname.trim()];
    if (func) {
      return await func.call(null, ...args);
    }
    throw new error(`function ${functionname} not found`);
  }

  async answer() {
    const historycontext = this.history;
    const prompt = `based on the following context, provide a complete, detailed and descriptive formated answer for the following task: ${this.query} .

context:
${historycontext}

task: "${this.query}"`;

    const finalanswer = await this.promptmodel(prompt);
    this.history.push(`answer: ${this.finalanswer}`);
    console.log("we will answer >>>>>>>", finalanswer);
    return finalanswer;
  }
}

module.exports = reactagent;

const ReActAgent = require("./ReactAgent.js");

async function main() {
  const query = "What does England border with?";
  const functions = [
    [
      "wikipedia",
      "params: query",
      "Semantic Search Wikipedia API for snippets, pageIds and sectionIds >> \n ex: Date brazil has been colonized? \n Brazil was colonized at 1500, pageId, sections : []",
    ],
    [
      "wikipedia_with_pageId",
      "params : pageId, sectionId",
      "Search Wikipedia API for data using a pageId and a sectionIndex as params.  \n ex: 1500, 1234 \n Section information about blablalbal",
    ],
  ];

  const agent = new ReActAgent(query, functions);
  try {
    const result = await agent.run();
    console.log("THE AGENT RETURN THE FOLLOWING >>>", result);
  } catch (e) {
    console.log("FAILED TO RUN T.T", e);
  }
}

main().catch(console.error);