I am currently utilizing this library to mock communication between my frontend app and an IRC gateway called webircgateway for my unit tests, and I wasn't able to find a function that can clear out the pending message queue within a test. I am testing whether my app can send out a message, and I currently have to copy and paste await server.nextMessage so that I can discard the IRC initial communication messages (PASS, NICK, and USER) which I don't care about so that I can then call toReceiveMessage and toHaveReceivedMessages on the PRIVMSG message, which I do care about.

I attempted to make my own makeshift flush function:

async function flushWebSocketMessages(server: WS) {
    while (1) {
        const result = await promiseWithTimeout(server.nextMessage);
        if (result === null) {
            break;
        }
    }
}

function promiseWithTimeout<T>(promise: Promise<T>) {
    return new Promise((resolve, reject) => {
        promise
            .then((val) => resolve(val))
            .catch((err) => reject(err));

        setTimeout(() => {
            resolve(null);
        }, 2000);
    });
}

However, it does not seem to work because once I clear out the queue (which happens when we cannot get any more messages and the 2s timeout returns null) any message I send through the WebSocket is reported by the mock server as undefined:

 expect(WS).toReceiveMessage(expected)

    Expected the next received message to equal:
      "PRIVMSG #mychannel :Hello there"
    Received:
      undefined

    Difference:

      Comparing two different types of values. Expected string but received undefined.

I have decided to work around this for the time being by copy and pasting await server.nextMessage like I mentioned earlier in order to clear out the queue, but I would like to know why this is happening if possible. Also, let me know if flushing the pending message queue is something that can benefit this project, thanks.