Experimental Websocket readyState returned as a string

[dougw-bc]

Brief summary

The experimental websocket encodes its internal readyState as a string.

https://developer.mozilla.org/en-US/docs/Web/API/WebSocket/readyState

In a browser this value is represented as an integer.

k6 version

v0.53.0

OS

Ubuntu, Windows 11

Docker version and image (if applicable)

N/A

Steps to reproduce the problem

Try to compare readyState to an integer, and it will not work as expected

Expected behaviour

WebSocket.readyState should expose integers rather than string values.

Actual behaviour

WebSocket.readyState returns a String instead of Integer

[mstoykov]

@dougw-bc can you please provide an exampe of this as it seems like the implementaiton is with integers and that has been the case for the last 2 years at least.

Are you sure you are not runnign a particularly old version of k6.

[dougw-bc]

I noticed this when trying to test an Elixir Phoenix Channel websocket server.

Here is the code that was not functioning as expected on k6:
https:/phoenixframework/phoenix/blob/main/assets/js/phoenix/socket.js#L525-L532

Updating this constant: https:/phoenixframework/phoenix/blob/main/assets/js/phoenix/constants.js#L5 now behaves 'correctly'

UPDATE: - this still behaves oddly, but not because of the websocket.readyState return value, it is something to do with the switch statement

Here is a reproduction of the issue with a small script:

import { WebSocket } from "k6/experimental/websockets";

export const options = {
  vus: 1,
  iterations: 1,
};

// this just hids the default it seems - maybe with any integer? 
function connectionState(state) {
  switch (state) {
    case 0:
      return "connecting";
    case 1:
      return "open";
    case 2:
      return "closing";
    case 3:
      return "closed";
    default:
      return "uh oh";
  }
}

export default async () => {
  const url = "wss://test-api.k6.io/ws/crocochat/publicRoom/";
  const socket = new WebSocket(url);

  socket.onopen = () => {
    console.log("connected! ", connectionState(socket.readyState));
  };

  socket.onclose = () => {
    console.log("closed! ", connectionState(socket.readyState));
  };

  console.log(connectionState(socket.readyState));

  const checkInterval = setInterval(() => {
    console.log(connectionState(socket.readyState));
  }, 250);

  setTimeout(function () {
    console.log(`Closing the socket`);
    socket.close();
    clearInterval(checkInterval);
  }, 3000);
};

This is on the following version: k6 v0.53.0 (commit/f82a27da8f, go1.22.6, linux/amd64)

My logs look like this:

INFO[0000] uh oh                                         source=console
INFO[0000] uh oh                                         source=console
INFO[0000] connected!  uh oh                     source=console
INFO[0000] uh oh                                         source=console
INFO[0000] uh oh                                         source=console
INFO[0001] uh oh                                         source=console
INFO[0001] uh oh                                         source=console
INFO[0001] uh oh                                         source=console
INFO[0001] uh oh                                         source=console
INFO[0002] uh oh                                         source=console
INFO[0002] uh oh                                         source=console
INFO[0002] uh oh                                         source=console
INFO[0002] uh oh                                         source=console
INFO[0003] Closing the socket                     source=console
INFO[0003] closed!  uh oh                            source=console

[dougw-bc]

After further testing - there might be something else going on with the switch statement itself - as this seems to work as expected:
Maybe this is a bug with switch?

const vals = { 0: "connecting", 1: "open", 2: "closing", 3: "closed" };

function connectionState(state) {
  return vals[state] || "uh oh";
}

[mstoykov]

Whank you for reportuing this 🙇

I managed to reproduce it and it seems to be a Sobek/goja bug where if you have type that is uint8 under the hood and return it goja/Sobek makes it into a string instead. But if you just return uint8 it works ... 🤦

I will try to go further to fix it in the goja/Sobek code, but until then I have made #80