this.subscribe = function()

in device/index.js [853:879]

• 27 lines of code
• 5 McCabe index (conditional complexity)

   this.subscribe = function(topics, options, callback) {
      if (!_filling() || autoResubscribe === false) {
         _updateSubscriptionCache('subscribe', topics, options); // we do not store callback in active cache
         //
         // If the 3rd argument (namely callback) is not present, we will
         // use two-argument form to call mqtt.Client#subscribe(), which
         // supports both subscribe(topics, options) and subscribe(topics, callback).
         //
         if (!isUndefined(callback)) {
            device.subscribe(topics, options, callback);
         } else {
            device.subscribe(topics, options);
         }
      } else {
         // we're offline - queue this subscription request
         if (offlineSubscriptionQueue.length < offlineSubscriptionQueueMaxSize) {
            offlineSubscriptionQueue.push({
               type: 'subscribe',
               topics: topics,
               options: options,
               callback: callback
            });
         } else {
            that.emit('error', new Error('Maximum queued offline subscription reached'));
         }
      }
   };