_autoScroll() {
      let elapsed, delta;

      if (this.amplitude) {
        elapsed = Date.now() - this.timestamp;
        delta = this.amplitude * Math.exp(-elapsed / this.options.duration);
        if (delta > 2 || delta < -2) {
          this._scroll(this.target - delta);
          requestAnimationFrame(this._autoScrollBound);
        } else {
          this._scroll(this.target);
        }
      }
    }
Auto scrolls to nearest carousel item.