我正在編輯我的Shopify主題的theme.js文件，以改變圖片輪播的默認屬性。我想有按鈕控制旋轉木馬循環開始和結束時，向后/向前。下面是旋轉木馬的代碼，我很難理解它的意思。任何幫助添加一個語句，檢查它是否在cc- start或cc-end，以將其偏移到正確的位置，將不勝感激！

// Initialises Featured Collection(s) carousels
  theme.carousels = {
    init: () => {
      var _this = this;

      _this.updateArrows = (carousel) => {
        var section = $(carousel).closest('.section, .cc-carousel-section')[0];

        if (carousel.scrollLeft < 15) {
          section.classList.add('cc-start');
        } else {
          section.classList.remove('cc-start');
        }

        if (carousel.scrollLeft + carousel.clientWidth > carousel.scrollWidth - 15) {
          section.classList.add('cc-end');
        } else {
          section.classList.remove('cc-end');
          section.classList.add('cc-carousel-scrolling');
        }
      };

      _this.initArrows = () => {
        var carousels = document.querySelectorAll(".cc-carousel");
        carousels.forEach((carousel) => {
          var $sectionContainer = $(carousel).closest('.section, .cc-carousel-section');
          var $carouselNext = $sectionContainer.find('.cc-carousel--next');
          var $carouselPrevious = $sectionContainer.find('.cc-carousel--previous');

          $carouselNext.addClass('cc-initialized');
          $carouselPrevious.addClass('cc-initialized');

          if ($carouselNext.length && $carouselPrevious.length) {
            $carouselNext.on('click.cc-carousel', function (evt) {
              evt.preventDefault();

              //Get the left hand edge of the next card out of view
              var nextLeftOffset = -1;
              var carouselOffsetLeft = $(this).closest('.section, .cc-carousel-section').find('.cc-carousel').offset().left;

              $(carousel).find('.column').each(function () {
                var offsetLeft = parseInt($(this).offset().left - carouselOffsetLeft);
                if (offsetLeft > carousel.scrollLeft + carousel.clientWidth - 20 && nextLeftOffset === -1) {
                  nextLeftOffset = offsetLeft;
                }
              });

              if (nextLeftOffset === -1) {
                nextLeftOffset = carousel.scrollLeft + carousel.clientWidth;
              }

              _this.scrollLeft(carousel, nextLeftOffset);
            });

            $carouselPrevious.on('click.cc-carousel', function (evt) {
              evt.preventDefault();

              //Get the left hand edge of the next card out of view
              var nextLeftOffset = -1;

              if (theme.viewport.isXs()) {
                var carouselOffsetLeft = $(this).closest('.section, .cc-carousel-section').find('.cc-carousel').offset().left;
                var prevLeftOffsets = {};

                $(carousel).find('.column').each(function (index) {
                  var offsetLeft = parseInt($(this).offset().left - carouselOffsetLeft);
                  if (offsetLeft >= 0 && nextLeftOffset === -1) {
                    if ($(this).hasClass('min-cols-2') && prevLeftOffsets[index - 2]) {
                      nextLeftOffset = carousel.scrollLeft + prevLeftOffsets[index - 2];
                    } else {
                      nextLeftOffset = carousel.scrollLeft + prevLeftOffsets[index - 1];
                    }
                  }

                  prevLeftOffsets[index] = offsetLeft;
                });
              }

              if (nextLeftOffset === -1) {
                nextLeftOffset = carousel.scrollLeft - carousel.clientWidth;
              }

              _this.scrollLeft(carousel, nextLeftOffset);
            });
          }

          _this.updateArrows(carousel);
        });
      };

      _this.scrollLeft = (carousel, left) => {
        carousel.classList.add('cc-carousel--smooth-scroll');
        carousel.scrollLeft = left;

        setTimeout(() => {
          _this.updateArrows(carousel);
          carousel.classList.remove('cc-carousel--smooth-scroll');
        }, 1000); // unsure about this number
      };

      _this.initMobileCarousels = () => {
        if (theme.viewport.isXs()) {
          var uninitializedMobCarousels = document.querySelectorAll(".cc-carousel-mobile:not(.cc-carousel)");
          uninitializedMobCarousels.forEach((carousel) => {
            carousel.classList.add('cc-carousel');
            var $sectionContainer = $(carousel).closest('.section, .cc-carousel-section');
            $sectionContainer.find('.cc-carousel--next').addClass('cc-initialized');
            $sectionContainer.find('.cc-carousel--previous').addClass('cc-initialized');
            $sectionContainer.addClass('cc-is-carousel');
          });
        } else {
          var initializedMobCarousels = document.querySelectorAll(".cc-carousel-mobile.cc-carousel");
          initializedMobCarousels.forEach((carousel) => {
            carousel.classList.remove('cc-carousel');
            var $sectionContainer = $(carousel).closest('.section, .cc-carousel-section');
            $sectionContainer.find('.cc-carousel--next').removeClass('cc-initialized');
            $sectionContainer.find('.cc-carousel--previous').removeClass('cc-initialized');
            $sectionContainer.removeClass('cc-is-carousel');
          });
        }
      };

      _this.initCarousels = () => {
        var carousels = document.querySelectorAll(".cc-carousel");

        if (carousels.length) {
          //Init click to drag on desktop browsers (except for Safari)
          if (theme.viewport.isSm() && !theme.browser.isSafari()) {
            carousels.forEach((carousel) => {
              var isDown = false,startX,scrollLeft;

              if (!carousel.classList.contains('cc-initialized')) {
                carousel.classList.add('cc-initialized');

                carousel.addEventListener("mousedown", (e) => {
                  isDown = true;
                  startX = e.pageX - carousel.offsetLeft;
                  scrollLeft = carousel.scrollLeft;
                });

                carousel.addEventListener("mouseleave", () => {
                  isDown = false;
                });

                carousel.addEventListener("mouseup", () => {
                  isDown = false;
                  _this.updateArrows(carousel);
                });

                carousel.addEventListener("mousemove", (e) => {
                  if (!isDown) return;
                  e.preventDefault();
                  var x = e.pageX - carousel.offsetLeft;
                  var walk = x - startX;
                  carousel.scrollLeft = scrollLeft - walk;
                  _this.updateArrows(carousel);
                });
              }
            });
          } else {
            carousels.forEach((carousel) => {
              //Update arrows on touch end
              carousel.addEventListener("touchend", () => {
                _this.updateArrows(carousel);
              });

              //Update arrows on scroll end
              var timer;
              carousel.addEventListener('scroll', () => {
                clearTimeout(timer);

                timer = setTimeout(() => {
                  _this.updateArrows(carousel);
                }, 300);
              }, { passive: true });
            });
          }

          //Init left/right buttons
          _this.initArrows();
        }
      };

      if (document.querySelectorAll(".cc-carousel-mobile").length) {
        $(window).off('debouncedresizewidth.cc-carousel').on('debouncedresizewidth.cc-carousel', _this.initMobileCarousels);
        _this.initMobileCarousels();
      }

      _this.initCarousels();
    },
    destroy: () => {
      var carousels = document.querySelector(".cc-carousel");
      if (carousels && carousels.length) {
        carousels.forEach((carousel) => {
          carousel.removeEventListener('mousedown').
          removeEventListener('mouseleave').
          removeEventListener('mouseup').
          removeEventListener('mousemove').
          classList.remove('cc-initialized');

          var $sectionContainer = $(carousel).closest('.section, .cc-carousel-section');
          $sectionContainer.find('.cc-carousel--previous').removeClass('cc-initialized');
          $sectionContainer.find('.cc-carousel--next').removeClass('cc-initialized');
        });
      }
      $(window).off('.cc-carousel');
    } };

  ;

曾嘗試使用偏移甚至滑離頁面，但無濟于事。