我有一个使用套接字IO的节点后端
first in app.js initialize初始化应用

const express = require("express")

const app = express()

module.exports = {
    app,
    express
}

然后在io.js中，我创建socket服务器，

const { app } = require("./app");
const http = require("http");
const socketio = require("socket.io");
const server = http.createServer(app);
const io = socketio(server);

module.exports = io;

然后在server.js中，首先导入用于API调用的app.js，然后导入io.js

require("dotenv").config();
const { app, express } = require("./app");
const logger = require("./logger");

const io = require("./io");

然后在server.js中添加emit listen代码

io.on("connection", (socket) => {
  console.log("we have a new connection");

  socket.on("disconnect", () => {
    console.log("the socket disconnected");
  });

  socket.on("join", ({ user_id }, callback) => {
    // const notification = getListNotifications(user_id);
    // const popup = getUserPopup(user_id);
    // socket.emit("nofication", { popup: popup.count, notification });
    socket.emit("nofication", { popup: 3, notificaton: { a: 1 } });
    socket.join(user.room);
    callback();
  });

然后我在开发模式下运行server.js文件nodemon server.js
然后在react中，我简单地使用socket.io

import io from "socket.io-client";

useEffect(() => {
    socket = io("ws://localhost:3009", {
      "force new connection": true,
      reconnectionAttempts: "Infinity",
      timeout: 10000,
      transports: ["websocket"],
    });

   

    return () => {
      socket.disconnect();
    };
  }, []);

它给了我这个错误在浏览器控制台

服务器node.js控制台正在接收https协议

我在其他答案中发现，这可能是一些协议问题。
很高兴向你学习。Thanks in advance