Turn a neopixel strip on and off via MQTT, in Espruino embedded Javascript

espruino_mqtt_neopixel.js

function mqttConnect(connVar) {
  var mqtt = require("MQTT");
  const MQTT_OPTIONS = {
    host: 'mqtt.host.net',
    keep_alive: 15,
    client_id: "espruino",
    username: "mqtt_username",
    password: "mqtt_password",
    path: '/doordash-temp'
  };

  if (!connVar) {
    var mqttConnection = mqtt.create(MQTT_OPTIONS.host, MQTT_OPTIONS);
    mqttConnect(mqttConnection);
    return mqttConnection;
  }

  if (connVar.connected) return connVar;

  connVar.on('error', function(err) {
    console.log(err);
  });
  connVar.on('connected', function() {
    console.log('MQTT connected, setting up subscriptions and polling');
    setTimeout(function() {
      connVar.subscribe(MQTT_OPTIONS.path, null, function() {
        console.log('subscribed to topic ' + MQTT_OPTIONS.path);
      });
    }, 1000);
  });
  connVar.on('publish', function(mqttMessage) {
    console.log(mqttMessage.message);
    ledMsg(mqttMessage.message);
  });
  /*connVar.on('message', function(mqttMessage) { // echo the channel name
    console.log('message: ' + mqttMessage);
  });*/
  connVar.on('close', function(err) {
    console.log(err);
  });
  connVar.on('end', function() {
    console.log('the end');
  });

  console.log('connecting');
  connVar.connect();
}

function onInit() {
  ledMsg('off');
  var wifi = require('Wifi');

  const WIFI_OPTIONS = {
    ssid: 'your_SSID',
    password: { password : 'password' },
    hostname: 'espruino-flashwork'
  };

  console.log('WiFi connecting');
  wifi.setHostname(WIFI_OPTIONS.hostname);
  wifi.stopAP();
  wifi.connect(WIFI_OPTIONS.ssid, WIFI_OPTIONS.password, function(ap){ 
    console.log('Wifi connected');
  });

  wifi.on('connected', function() {
    console.log(wifi.getIP());
    setInterval(function() {
      var connVar = mqttConnect(); // need to feed previous object
    }, 30 * 1000);
  });
  wifi.on('disconnected', function() {
    console.log('Disconnected from WiFi');
    //connVar.disconnect();
  });
}

function ledMsg(msg) {
  var led_count = 8;
  var rgb = new Uint8ClampedArray(led_count * 3);
  var neoPin = NodeMCU.D4;

  var pos = 0;
  function getPattern() {
    pos++;
    for (var i=0;i<rgb.length;) {
      rgb[i++] = (1 + Math.sin((i+pos)*0.1324)) * 127;
      rgb[i++] = (1 + Math.sin((i+pos)*0.1654)) * 127;
      rgb[i++] = (1 + Math.sin((i+pos)*0.1)) * 127;
    }
    return rgb;
  }

  if (msg === 'off') {
  clearInterval(interval);
    for (var i=0;i<rgb.length;) {
      rgb[i++] = 0;
      rgb[i++] = 0;
      rgb[i++] = 0;
    }
    require("neopixel").write(neoPin, rgb);
  } else {
    // Produce an animated rainbow
    interval = setInterval(function() {
      require("neopixel").write(neoPin, getPattern());
    }, 100);
  }
}