simple ping pong socket.io example failing after a short time (data payload undefined)

[jt0dd]

You want to:

• report a bug
• request a feature

Current behaviour

What is actually happening?

simple ping pong socket.io example failing after a short time (data payload undefined)

Steps to reproduce

I have a very barebones socket.io example (between node.js client and server) I built because my overall socket.io connection kept reconnecting and this is an effort to debug what's going wrong:

socket-server.js

const app = require('express')();
const server = require('http').Server(app);
const io = require('socket.io')(server);
server.listen(8080);
console.log("listening...")
let counter = 0;
setInterval(() => {
  let data = { beat: counter };
  console.log("sending ping", data);
  io.sockets.emit('ping', data);
  counter++;
}, 1000);
io.on("connection", (socket) => {
  console.log("connected to client");
  socket.on("pong", (data) => {
    console.log("pong", data.beat);
  });
});

socket-client.js

var io = require('socket.io-client')
var socket = io.connect('http://127.0.0.1:8080/', {
  reconnect: true
});
socket.on('connect', function(socket) {
  console.log('connected to server');
});
socket.on('ping', function(data) {
  socket.emit('pong', data);
  console.log('ping', data.beat );
});

I start the server and then a few moments later start the client (server and client both node.js in two separate command prompts) (Windows).

Output of socket-server.js:

listening...
sending ping { beat: 0 }
sending ping { beat: 1 }
sending ping { beat: 2 }
connected to client
sending ping { beat: 3 }
sending ping { beat: 4 }
sending ping { beat: 5 }
sending ping { beat: 6 }
sending ping { beat: 7 }
sending ping { beat: 8 }
sending ping { beat: 9 }
sending ping { beat: 10 }
sending ping { beat: 11 }
sending ping { beat: 12 }
sending ping { beat: 13 }
sending ping { beat: 14 }
sending ping { beat: 15 }
sending ping { beat: 16 }
sending ping { beat: 17 }
sending ping { beat: 18 }
sending ping { beat: 19 }
sending ping { beat: 20 }
sending ping { beat: 21 }
sending ping { beat: 22 }
sending ping { beat: 23 }
sending ping { beat: 24 }
sending ping { beat: 25 }
sending ping { beat: 26 }
sending ping { beat: 27 }
sending ping { beat: 28 }
sending ping { beat: 29 }
sending ping { beat: 30 }
sending ping { beat: 31 }
sending ping { beat: 32 }

Output of socket-client.js:

connected to server
ping 3
ping 4
ping 5
ping 6
ping 7
ping 8
ping 9
ping 10
ping 11
ping 12
ping 13
ping 14
ping 15
ping 16
ping 17
ping 18
ping 19
ping 20
ping 21
ping 22
ping 23
ping 24
ping 25
ping 26
ping 27
C:\Users\jonat\..proj-path..\tests\socket-client.js:10
  console.log('ping', data.beat );
                           ^

TypeError: Cannot read property 'beat' of undefined
    at Socket.<anonymous> (C:\Users\jonat\..proj-path..\tests\socket-client.js:10:28)

Expected behaviour

I would expect this simple example over localhost to not break down. Since the connection over localhost, my network quality wouldn't be causing a breakdown of the connection, so what gives? How can I debug / fix this?

Setup

• v12.16.1:
• Windows:
• runtime:
• socket.io@2.3.0 & socket.io-client:
  (No browser involved)

Notes

I tried:

• reinstalling socket.io
• downgrading to 2.2.0
• changing the ports to 3000 instead of 8080
• restarting my PC

[jt0dd]

ping and pong are reserved events, hence the behavior. til