vue axios. promise接口请求函数retur

async getcategoryListTwo() {
    let arraylist = []
    let params = {
         parentId: id
    };
    let res = await $http.getTwoCategoryList(params);
    if(res && res.result && res.status.statusCode == 0) {
        arraylist = res.result
    } else {
        this.$customMessage(res.status.statusReason, "error");
    }
        return arraylist
}

let childrenlist = this.getcategoryListTwo(item.id)
childrenlist.then(function(result) {
       item.children = result
})