code: function() {
        var rules = this.component.getAllProperties('rrule');
        var i = 0;
        var len = rules.length;
        var result = Object.create(null);
  
        for (; i < len; i++) {
          var value = rules[i].getFirstValue();
          result[value.freq] = true;
        }
  
        return result;
      }
docs: Returns the types of recurrences this event may have.
  
  Returned as an object with the following possible keys:
  
  - YEARLY
  - MONTHLY
  - WEEKLY
  - DAILY
  - MINUTELY
  - SECONDLY
  
  @return {Object.<ICAL.Recur.frequencyValues, Boolean>}
  Object of recurrence flags