swiper/src/components/core/loop/loopFix.js

Most modern mobile touch slider and framework with hardware accelerated transitions

export default function () {
  const swiper = this;

  swiper.emit('beforeLoopFix');

  const {
    activeIndex, slides, loopedSlides, allowSlidePrev, allowSlideNext, snapGrid, rtlTranslate: rtl,
  } = swiper;
  let newIndex;
  swiper.allowSlidePrev = true;
  swiper.allowSlideNext = true;

  const snapTranslate = -snapGrid[activeIndex];
  const diff = snapTranslate - swiper.getTranslate();

  // Fix For Negative Oversliding
  if (activeIndex < loopedSlides) {
    newIndex = (slides.length - (loopedSlides * 3)) + activeIndex;
    newIndex += loopedSlides;
    const slideChanged = swiper.slideTo(newIndex, 0, false, true);
    if (slideChanged && diff !== 0) {
      swiper.setTranslate((rtl ? -swiper.translate : swiper.translate) - diff);
    }
  } else if (activeIndex >= slides.length - loopedSlides) {
    // Fix For Positive Oversliding
    newIndex = -slides.length + activeIndex + loopedSlides;
    newIndex += loopedSlides;
    const slideChanged = swiper.slideTo(newIndex, 0, false, true);
    if (slideChanged && diff !== 0) {
      swiper.setTranslate((rtl ? -swiper.translate : swiper.translate) - diff);
    }
  }
  swiper.allowSlidePrev = allowSlidePrev;
  swiper.allowSlideNext = allowSlideNext;

  swiper.emit('loopFix');
}