next(n) {
      if (n === undefined || isNaN(n)) {
        n = 1;
      }

      let index = this.center + n;
      if (index >= this.count || index < 0) {
        if (this.noWrap) {
          return;
        }

        index = this._wrap(index);
      }
      this._cycleTo(index);
    }
Cycle to next item
@param {Number} [n]