code: function Buffering(options) {
      events.EventEmitter.call(this);
  
      options = options || {};
  
      if (options.useUnique) {
          var newOptions = {};
          Object.keys(options).forEach(function(key) {
              if (key != 'useUnique') newOptions[key] = options[key];
          });
          return new UniqueBuffering(newOptions);
      }
  
      this._timeThreshold = (typeof options.timeThreshold === 'undefined') ? -1 : options.timeThreshold;
      this._sizeThreshold = (typeof options.sizeThreshold === 'undefined') ? -1 : options.sizeThreshold;
      this._data = [];
      this._flushTimer = null;
      this._paused = false;
      this._resumeTimer = null;
      this._flushingBySize = false;
  }
docs: ES 5+ will handle null and undefined