swiper/src/components/core/update/updateProgress.js

Most modern mobile touch slider and framework with hardware accelerated transitions

import Utils from '../../../utils/utils';

export default function (translate = (this && this.translate) || 0) {
  const swiper = this;
  const params = swiper.params;

  const translatesDiff = swiper.maxTranslate() - swiper.minTranslate();
  let { progress, isBeginning, isEnd } = swiper;
  const wasBeginning = isBeginning;
  const wasEnd = isEnd;
  if (translatesDiff === 0) {
    progress = 0;
    isBeginning = true;
    isEnd = true;
  } else {
    progress = (translate - swiper.minTranslate()) / (translatesDiff);
    isBeginning = progress <= 0;
    isEnd = progress >= 1;
  }
  Utils.extend(swiper, {
    progress,
    isBeginning,
    isEnd,
  });

  if (params.watchSlidesProgress || params.watchSlidesVisibility) swiper.updateSlidesProgress(translate);

  if (isBeginning && !wasBeginning) {
    swiper.emit('reachBeginning toEdge');
  }
  if (isEnd && !wasEnd) {
    swiper.emit('reachEnd toEdge');
  }
  if ((wasBeginning && !isBeginning) || (wasEnd && !isEnd)) {
    swiper.emit('fromEdge');
  }

  swiper.emit('progress', progress);
}