index.js

import {
  NativeEventEmitter,
  NativeModules
} from 'react-native';

var Mqtt = NativeModules.Mqtt;

var MqttClient = function(options, clientRef){
  this.options = options;
  this.clientRef = clientRef;
  this.eventHandler = {};

  this.dispatchEvent = function(data) {

    if(data && data.clientRef == this.clientRef && data.event) {

      if(this.eventHandler[data.event]) {
        this.eventHandler[data.event](data.message);
      }
    }
  }
}

MqttClient.prototype.on = function (event, callback) {
  console.log('setup event', event);
  this.eventHandler[event] = callback;
}

MqttClient.prototype.connect = function () {
  Mqtt.connect(this.clientRef);
}

MqttClient.prototype.disconnect = function () {
  Mqtt.disconnect(this.clientRef);
}

MqttClient.prototype.subscribe = function (topic, qos) {
  Mqtt.subscribe(this.clientRef, topic, qos);
}

MqttClient.prototype.unsubscribe = function (topic) {
  Mqtt.unsubscribe(this.clientRef, topic);
}

MqttClient.prototype.publish = function(topic, payload, qos, retain) {
  Mqtt.publish(this.clientRef, topic, payload, qos, retain);
}

const emitter = new NativeEventEmitter(Mqtt)

module.exports = {
  clients: [],
  eventHandler: null,
  dispatchEvents: function(data) {
    this.clients.forEach(function(client) {
      client.dispatchEvent(data);
    });
  },
  createClient: async function(options) {
    if(options.uri) {
      var pattern = /^((mqtt[s]?|ws[s]?)?:(\/\/)([0-9a-zA-Z_\.]*):?(\d+))$/;
      var matches = options.uri.match(pattern);
      var protocol = matches[2];
      var host = matches[4];
      var port =  matches[5];

      options.port = parseInt(port);
      options.host = host;
      options.protocol = 'tcp';


      if(protocol == 'wss' || protocol == 'mqtts') {
        options.tls = true;
      }
      if(protocol == 'ws' || protocol == 'wss') {
        options.protocol = 'ws';
      }

    }

    let clientRef = await Mqtt.createClient(options);

    var client = new MqttClient(options, clientRef);

    /* Listen mqtt event */
    if(this.eventHandler === null) {
      console.log('add mqtt_events listener')
      this.eventHandler = emitter.addListener(
        "mqtt_events",
        (data) => this.dispatchEvents(data));
    }
    this.clients.push(client);

    return client;
  },
  removeClient: function(client) {
    var clientIdx = this.clients.indexOf(client);

    if(clientIdx > -1)
      this.clients.splice(clientIdx, 1);

    if(this.clients.length > 0) {
      this.eventHandler.remove();
      this.eventHandler = null;
    }

    Mqtt.removeClient(client.clientRef);
  }

};