解决 elementui el-cascader组件懒加载时存在选中状态丢失的问题？

解决 elementui el-cascader组件懒加载时存在选中状态丢失的问题？

<el-cascader 
  ref="cascader" 
  v-model="curList" 
  :show-all-levels="false" 
  :options="classList"
  :props="cascaderProps"
  clearable
  filterable
  style="width: 100%"
  placeholder="选择"
  @change="handleChange"
/>

data(){
	return{
		curList:[],
		classList:[],
		cascaderProps: {
		  checkStrictly: true,
		  multiple: true,
		  children: 'sonList',
		  value: 'id',
		  label: 'name',
		  leaf: 'leaf',
		  lazy: true,
		  lazyLoad: this.lazyLoadCascader
        }
	}
},
methods:{
	async lazyLoadCascader(node, resolve) {
      const { checked } = node
      if (node.level === 0) {
        const list = await this.getClassList(1) // 获取数据，返回数组类型
        this.externalKnowclassList = list
        this.initSelectedCascaderdata() // 修改操作,初始化已选节点
        // eslint-disable-next-line require-atomic-updates
        node.data = list
        resolve(list)
      } else {
        const { id, type, sonList } = node.data
        if (this.$utils.isNotEmptyArray(sonList)) {
          resolve([])
        } else {
          const list = await this.getClassList(type + 1, id) // 获取数据，返回数组类型
          // eslint-disable-next-line require-atomic-updates
          node.data.sonList = list
          resolve(list)
        }
        // 解决 el-cascader 懒加载时选中状态丢失的问题
        const cascader = this.$refs.cascader
        node.doCheck(checked) // 更新节点的选中状态
        cascader.panel.handleExpand(node) // 展开当前节点
        cascader.panel.calculateMultiCheckedValue() // 重新计算多选状态下的选中值
      }
    },
}