element中el-cascader级联 下拉选择-可单独多选（整理）

<el-cascader :options="regionsData" v-model="rankData.platform"
            :props="{value: 'id', label: 'name', children: 'child', multiple: true, checkStrictly: true }"
            collapse-tags></el-cascader>

var newArr = []
var aa = [];
var bb = [];
// console.log(row, '262---------')
// console.log(row.area_list, '263---------')
for (var j = 0; j < row.bind.length; j++) {
  aa.push([row.bind[j].province_id,row.bind[j].city_id])
  bb.push([row.bind[j].province_id,row.bind[j].city_id,row.bind[j].area_id])
}
this.rankData.areaIdAll = [...aa,...bb];  //就处理成需要回显的数据了