Feature request: Add a way to return topic with message

[henhen724]

When subscribing to wildcards a way to identify the particular topic which sent the message would be useful. If the asyncIterator returned two arguments message, topic, you could implement pubSubs that use this.

[henhen724]

private onMessage(topic: string, message: Buffer) {
    const subscribers = [].concat(
        ...Object.keys(this.subsRefsMap)
        .filter((key) => MQTTPubSub.matches(key, topic))
        .map((key) => this.subsRefsMap[key]),
    );

    // Don't work for nothing..
    if (!subscribers || !subscribers.length) {
      return;
    }
    const messageString = message.toString(this.parseMessageWithEncoding);
    let parsedMessage;
    try {
      parsedMessage = JSON.parse(messageString);
      parsedMessage = { ...parsedMessage, topic };
    } catch (e) {
      parsedMessage = messageString;
    }

    for (const subId of subscribers) {
      const listener = this.subscriptionMap[subId][1];
      listener(parsedMessage);
    }
  }

This isn't a perfect fix but it adds the feature for people using JSON MQTT packets

The issue is to add this really you want to return {message: parsedMessage, topic} to the listener, but that would break all existing projects using this package.

[henhen724]

Any progress on this?

[henhen724]

I've implemented this feature in an up to date fork of this repository. If you would like, I can submit a merge request.

[henhen724]

Hey will this pull request ever be added to main branch. It passes all tests, adds a useful feature, and has been idle for over a year?