Socket.io: Overwritten generateId() gets executed, but the returned id seems to be ignored

问题

I am trying to overwrite generateId. I used for that the example from the docs. But the behaviour is strange. generateId gets executed, but socket.id is like a regular id, instead of the desired result "custom:id:" + 1.

Code

const express = require('express');
const socketIO = require('socket.io');
const http = require('http');

const app = express();
app.set('port', 5000);
const server = http.Server(app);
const io = socketIO(server);


io.engine.generateId = (req) => {
    console.log('This here gets printed')
    return "custom:id:" + 1;
}

io.on('connection', socket => {
    console.log(socket.id);
})


server.listen(5000, async () => {
    console.log('Starting server on port 5000');
});

Expected Output: custom:id:1

Actual Output: MNWAC86CdPXB7thTAAAA

package.json Dependencies

  "dependencies": {
    "base64id": "^2.0.0",
    "clean-webpack-plugin": "^3.0.0",
    "cookie": "^0.4.1",
    "css-loader": "^5.0.1",
    "express": "^4.17.1",
    "file-loader": "^6.2.0",
    "html-webpack-plugin": "^4.5.0",
    "jquery": "^3.5.1",
    "ngrok": "^3.4.0",
    "sass": "^1.29.0",
    "sass-loader": "^10.1.0",
    "socket-io": "^1.0.0",
    "socket.io": "^3.0.3",
    "socket.io-client": "^3.0.3",
    "style-loader": "^2.0.0",
    "webpack": "^5.7.0",
    "webpack-dev-middleware": "^4.0.2"
  }

来源：https://stackoverflow.com/questions/65471836/socket-io-overwritten-generateid-gets-executed-but-the-returned-id-seems-to