docs: function() {
          var inRange = false;
  
          if (this.alwaysInRange) {
              inRange = true;
          } else {
              if (this.map) {
                  var resolution = this.map.getResolution();
                  inRange = ( (resolution >= this.minResolution) &&
                              (resolution <= this.maxResolution) );
              }
          }
          return inRange;
      }