使用递归 向数组中添加某字段

 created() {
      this.addLevel(this.treeData); // 数组
 }
methods:{
    addLevel (array, i = 1) {
            let tableList = (arr, i) => {
                arr.forEach(item => {
                    item.level = i;
                    if (item.children && item.children.length) {
                        return this.addLevel(item.children, i + 1);
                    }
                });
            };
            return tableList(array, i);
        },
}