js遍历树形结构并返回所有的子节点id值

lookForAllId(data = [], arr = []) {
      for (let item of data) {
        arr.push(item.id);
        if (item.children && item.children.length)
          this.lookForAllId(item.children, arr);
      }
      return arr;
    },

//调用

this.lookForAllId(this.treeArry) //treeArry是树形结构