version:element-plus 1.0.1-beta.0
<template>
<transition v-on="on">
<slot></slot>
</transition>
</template>
<script lang='ts'>
import {
addClass, removeClass } from '@element-plus/utils/dom'
export default {
name: 'ElCollapseTransition',
setup() {
return {
// https://cn.vuejs.org/v2/api/#transition
on: {
beforeEnter(el) {
// 根元素class添加'collapse-transition'
addClass(el, 'collapse-transition')</