How to connect server and client with socket io over different api?

Question

In this code the socket connection is established between client and server which sends current timestamp every second. Everything is working fine. Only one problem, in client side i want to use endpoint as http://127.0.0.1:4001/api instead of http://127.0.0.1:4001/ what should be done is server side to acheive this?

server side----app.js

const express = require("express");
const http = require("http");
const socketIo = require("socket.io");

const port = process.env.PORT || 4001;
const index = require("./index");

const app = express();
app.use(index);

const server = http.createServer(app);

const io = socketIo(server);

let interval;

io.on("connection", (socket) => {
  console.log("New client connected");
  if (interval) {
    clearInterval(interval);
  }
  interval = setInterval(() => getApiAndEmit(socket), 1000);
  socket.on("disconnect", () => {
    console.log("Client disconnected");
    clearInterval(interval);
  });
});

const getApiAndEmit = socket => {
  const response = new Date();
  // Emitting a new message. Will be consumed by the client
  socket.emit("FromAP", response);
};

server.listen(port, () => console.log(`Listening on port ${port}`));

server side----index.js

const express = require("express");
const router = express.Router();

router.get("/", (req, res) => {
  res.send({ response: "I am alive" }).status(200);
});

router.get("/api", (req, res) => {
    res.send({ response: "I am jai" }).status(200);
  });

module.exports = router;

clent side---app.js

import React, { useState, useEffect } from "react";
import socketIOClient from "socket.io-client";
const ENDPOINT = "http://127.0.0.1:4001/";

function App() {
  const [response, setResponse] = useState("");

  useEffect(() => {
    const socket = socketIOClient(ENDPOINT);
    socket.on("FromAP", data => {
      setResponse(data);
    });
  }, []);

  return (
    <p>
      It's <time dateTime={response}>{response}</time>
    </p>
  );
}

export default App;