el-cascader重置级联面板

<template>
    <div class='cascaderRecovery'>
      <el-cascader
        v-model="value"
        :options="options"
        ref="cascaderRef"
        @visible-change="handleVisibleChange"
        clearable>
      </el-cascader>
    </div>
</template>

<script>
export default {
  name: 'cascaderRecovery',
  data () {
    return {
      value: [],
      options: [{
        value: '*n',
        label: '指南',
        children: [{
          value: 'shejiyuanze',
          label: '设计原则',
          children: [{
            value: 'yizhi',
            label: '一致'
          }, {
            value: 'fankui',
            label: '反馈'
          }, {
            value: 'xiaolv',
            label: '效率'
          }, {
            value: 'kekong',
            label: '可控'
          }]
        }, {
          value: 'daohang',
          label: '导航',
          children: [{
            value: 'cexiangdaohang',
            label: '侧向导航'
          }, {
            value: 'dingbudaohang',
            label: '顶部导航'
          }]
        }]
      }, {
        value: 'zujian',
        label: '组件',
        children: [{
          value: 'basic',
          label: 'Basic',
          children: [{
            value: 'layout',
            label: 'Layout 布局'
          }, {
            value: 'color',
            label: 'Color 色彩'
          }, {
            value: 'typography',
            label: 'Typography 字体'
          }, {
            value: 'icon',
            label: 'Icon 图标'
          }, {
            value: 'button',
            label: 'Button 按钮'
          }]
        }, {
          value: 'form',
          label: 'Form',
          children: [{
            value: 'radio',
            label: 'Radio 单选框'
          }, {
            value: 'checkbox',
            label: 'Checkbox 多选框'
          }, {
            value: 'input',
            label: 'Input 输入框'
          }, {
            value: 'input-number',
            label: 'InputNumber 计数器'
          }, {
            value: 'select',
            label: 'Select 选择器'
          }, {
            value: 'cascader',
            label: 'Cascader 级联选择器'
          }, {
            value: 'switch',
            label: 'Switch 开关'
          }, {
            value: 'slider',
            label: 'Slider 滑块'
          }, {
            value: 'time-picker',
            label: 'TimePicker 时间选择器'
          }, {
            value: 'date-picker',
            label: 'DatePicker 日期选择器'
          }, {
            value: 'datetime-picker',
            label: 'DateTimePicker 日期时间选择器'
          }, {
            value: 'upload',
            label: 'Upload 上传'
          }, {
            value: 'rate',
            label: 'Rate 评分'
          }, {
            value: 'form',
            label: 'Form 表单'
          }]
        }, {
          value: 'data',
          label: 'Data',
          children: [{
            value: 'table',
            label: 'Table 表格'
          }, {
            value: 'tag',
            label: 'Tag 标签'
          }, {
            value: 'progress',
            label: 'Progress 进度条'
          }, {
            value: 'tree',
            label: 'Tree 树形控件'
          }, {
            value: 'pagination',
            label: 'Pagination 分页'
          }, {
            value: 'badge',
            label: 'Badge 标记'
          }]
        }, {
          value: 'notice',
          label: 'Notice',
          children: [{
            value: 'alert',
            label: 'Alert 警告'
          }, {
            value: 'loading',
            label: 'Loading 加载'
          }, {
            value: 'message',
            label: 'Message 消息提示'
          }, {
            value: 'message-box',
            label: 'MessageBox 弹框'
          }, {
            value: 'notification',
            label: 'Notification 通知'
          }]
        }, {
          value: 'navigation',
          label: 'Navigation',
          children: [{
            value: 'menu',
            label: 'NavMenu 导航菜单'
          }, {
            value: 'tabs',
            label: 'Tabs 标签页'
          }, {
            value: 'breadcrumb',
            label: 'Breadcrumb 面包屑'
          }, {
            value: 'dropdown',
            label: 'Dropdown 下拉菜单'
          }, {
            value: 'steps',
            label: 'Steps 步骤条'
          }]
        }, {
          value: 'others',
          label: 'Others',
          children: [{
            value: 'dialog',
            label: 'Dialog 对话框'
          }, {
            value: 'tooltip',
            label: 'Tooltip 文字提示'
          }, {
            value: 'popover',
            label: 'Popover 弹出框'
          }, {
            value: 'card',
            label: 'Card 卡片'
          }, {
            value: 'carousel',
            label: 'Carousel 走马灯'
          }, {
            value: 'collapse',
            label: 'Collapse 折叠面板'
          }]
        }]
      }, {
        value: 'ziyuan',
        label: '资源',
        children: [{
          value: 'axure',
          label: 'Axure Components'
        }, {
          value: 'sketch',
          label: 'Sketch Templates'
        }, {
          value: 'jiaohu',
          label: '组件交互文档'
        }]
      }]
    }
  },
  methods: {
    handleVisibleChange (flag) {
      if (flag && this.$refs.cascaderRef.getCheckedNodes().length === 0) {
        // 重置**路径，级联下拉框恢复默认，收起展开节点路径面板
        this.$refs.cascaderRef.panel.activePath = []
        this.$refs.cascaderRef.panel.syncActivePath()
      }
    }
  }
}
</script>