code: function(component, propertyName) {
        function handleProp(prop) {
          idx = ICAL.helpers.binsearchInsert(
            result,
            prop,
            compareTime
          );
  
          // ordered insert
          result.splice(idx, 0, prop);
        }
  
        var result = [];
        var props = component.getAllProperties(propertyName);
        var len = props.length;
        var i = 0;
        var prop;
  
        var idx;
  
        for (; i < len; i++) {
          props[i].getValues().forEach(handleProp);
        }
  
        return result;
      }
docs: Extract all dates from the properties in the given component. The
  properties will be filtered by the property name.
  
  @private
  @param {ICAL.Component} component        The component to search in
  @param {String} propertyName             The property name to search for
  @return {ICAL.Time[]}                    The extracted dates.