text: import { addClass, removeClass } from 'element-ui-international/src/utils/dom';
  
  class Transition {
    beforeEnter(el) {
      addClass(el, 'collapse-transition');
      if (!el.dataset) el.dataset = {};
  
      el.dataset.oldPaddingTop = el.style.paddingTop;
      el.dataset.oldPaddingBottom = el.style.paddingBottom;
  
      el.style.height = '0';
      el.style.paddingTop = 0;
      el.style.paddingBottom = 0;
    }
  
    enter(el) {
      el.dataset.oldOverflow = el.style.overflow;
      if (el.scrollHeight !== 0) {
        el.style.height = el.scrollHeight + 'px';
        el.style.paddingTop = el.dataset.oldPaddingTop;
        el.style.paddingBottom = el.dataset.oldPaddingBottom;
      } else {
        el.style.height = '';
        el.style.paddingTop = el.dataset.oldPaddingTop;
        el.style.paddingBottom = el.dataset.oldPaddingBottom;
      }
  
      el.style.overflow = 'hidden';
    }
  
    afterEnter(el) {
      // for safari: remove class then reset height is necessary
      removeClass(el, 'collapse-transition');
      el.style.height = '';
      el.style.overflow = el.dataset.oldOverflow;
    }
  
    beforeLeave(el) {
      if (!el.dataset) el.dataset = {};
      el.dataset.oldPaddingTop = el.style.paddingTop;
      el.dataset.oldPaddingBottom = el.style.paddingBottom;
      el.dataset.oldOverflow = el.style.overflow;
  
      el.style.height = el.scrollHeight + 'px';
      el.style.overflow = 'hidden';
    }
  
    leave(el) {
      if (el.scrollHeight !== 0) {
        // for safari: add class after set height, or it will jump to zero height suddenly, weired
        addClass(el, 'collapse-transition');
        el.style.height = 0;
        el.style.paddingTop = 0;
        el.style.paddingBottom = 0;
      }
    }
  
    afterLeave(el) {
      removeClass(el, 'collapse-transition');
      el.style.height = '';
      el.style.overflow = el.dataset.oldOverflow;
      el.style.paddingTop = el.dataset.oldPaddingTop;
      el.style.paddingBottom = el.dataset.oldPaddingBottom;
    }
  }
  
  export default {
    name: 'ElCollapseTransition',
    functional: true,
    render(h, { children }) {
      const data = {
        on: new Transition()
      };
  
      return h('transition', data, children);
    }
  };
  