<ul class="el-cascader-menu__list" style="border-top: solid 1px #E4E7ED;padding:0">
 <li class="el-cascader-node" style="height:38px;line-height: 38px">
  <i class="el-icon-plus"></i>
  <span class="el-cascader-node__label">新增商品分类</span>
  <i class="el-icon-arrow-right el-cascader-node__postfix"/>
 </li>
</ul>

/**
 * 为element-ui的Select和Cascader添加弹层底部操作按钮
 * @param visible
 * @param refName 设定的ref名称
 * @param onClick 底部操作按钮点击监听
 */
visibleChange(visible, refName, onClick) {
 if (visible) {
  const ref = this.$refs[refName];
  let popper = ref.$refs.popper;
  if (popper.$el) popper = popper.$el;
  if (!Array.from(popper.children).some(v => v.className === 'el-cascader-menu__list')) {
   const el = document.createElement('ul');
   el.className = 'el-cascader-menu__list';
   el.style = 'border-top: solid 1px #E4E7ED; padding:0; color: #606266;';
   el.innerHTML = `<li class="el-cascader-node" style="height:38px;line-height: 38px">
<i class="el-icon-menu"></i>
<span class="el-cascader-node__label">商品分类管理</span>
<i class="el-icon-arrow-right el-cascader-node__postfix"/>
</li>`;
   popper.appendChild(el);
   el.onclick = () => {
    // 底部按钮的点击事件 点击后想触发的逻辑也可以直接写在这
    onClick && onClick();

    // 以下代码实现点击后弹层隐藏 不需要可以删掉
    if (ref.toggleDropDownVisible) {
     ref.toggleDropDownVisible(false);
    } else {
     ref.visible = false;
    }
   };
  }
 }
},

<el-cascader
  :options="cascaderOptions"
  v-model="cascaderValue"
  @visible-change="v => visibleChange(v, 'cascader', cascaderClick)"
  ref="cascader"
/>

const selectBottomAction = {
 methods: {
  /**
   * 为element-ui的Select和Cascader添加弹层底部操作按钮
   * @visible-change="v => selectBottomAction(v, {ref: 'select', label: '商品分类' , icon: 'el-icon-menu', click: goodsTypeManagement})"
   * @param visible
   * @param ref   设定的ref名称
   * @param click  底部操作按钮点击监听
   * @param label  标题
   * @param icon   图标class
   * @param arrow  是否显示箭头
   */
  selectBottomAction(visible, {ref, click, label = '', icon = '', arrow = false}) {
   if (visible) {
    const _ref = this.$refs[ref];
    let popper = _ref.$refs.popper;
    if (popper.$el) popper = popper.$el;
    if (!Array.from(popper.children).some(v => v.className === 'el-cascader-menu__list')) {
     const el = document.createElement('ul');
     el.className = 'el-cascader-menu__list';
     el.style = 'border-top: solid 1px #E4E7ED; padding: 0; color: #606266;';
     el.innerHTML = `<li class="el-cascader-node" style="height:38px;line-height: 38px">
     ${icon "${icon}"></i>` : ''}
     <span class="el-cascader-node__label">${label}</span>
     ${arrow "el-icon-arrow-right el-cascader-node__postfix"/>' : ''}
     </li>`;
     popper.appendChild(el);
     el.onclick = () => {
      click && click();
      if (_ref.toggleDropDownVisible) {
       _ref.toggleDropDownVisible(false);
      } else {
       _ref.visible = false;
      }
     };
    }
   }
  },
 },
};

export default selectBottomAction;