swiper/core/loop/loopCreate.js

import { getDocument } from 'ssr-window';
import $ from '../../shared/dom.js';
export default function loopCreate() {
  const swiper = this;
  const document = getDocument();
  const {
    params,
    $wrapperEl
  } = swiper; // Remove duplicated slides

  const $selector = $($wrapperEl.children()[0].parentNode);
  $selector.children(`.${params.slideClass}.${params.slideDuplicateClass}`).remove();
  let slides = $selector.children(`.${params.slideClass}`);

  if (params.loopFillGroupWithBlank) {
    const blankSlidesNum = params.slidesPerGroup - slides.length % params.slidesPerGroup;

    if (blankSlidesNum !== params.slidesPerGroup) {
      for (let i = 0; i < blankSlidesNum; i += 1) {
        const blankNode = $(document.createElement('div')).addClass(`${params.slideClass} ${params.slideBlankClass}`);
        $selector.append(blankNode);
      }

      slides = $selector.children(`.${params.slideClass}`);
    }
  }

  if (params.slidesPerView === 'auto' && !params.loopedSlides) params.loopedSlides = slides.length;
  swiper.loopedSlides = Math.ceil(parseFloat(params.loopedSlides || params.slidesPerView, 10));
  swiper.loopedSlides += params.loopAdditionalSlides;

  if (swiper.loopedSlides > slides.length) {
    swiper.loopedSlides = slides.length;
  }

  const prependSlides = [];
  const appendSlides = [];
  slides.each((el, index) => {
    const slide = $(el);

    if (index < swiper.loopedSlides) {
      appendSlides.push(el);
    }

    if (index < slides.length && index >= slides.length - swiper.loopedSlides) {
      prependSlides.push(el);
    }

    slide.attr('data-swiper-slide-index', index);
  });

  for (let i = 0; i < appendSlides.length; i += 1) {
    $selector.append($(appendSlides[i].cloneNode(true)).addClass(params.slideDuplicateClass));
  }

  for (let i = prependSlides.length - 1; i >= 0; i -= 1) {
    $selector.prepend($(prependSlides[i].cloneNode(true)).addClass(params.slideDuplicateClass));
  }
}