树形结构中根据id获取指定节点

/**
   * @description: 根据id获取指定节点
   * @params: id-要查询的节点id
   * @params: tree-树形结构的数组
   * @return: 要查找的节点对象  
  **/
  var getItemByIdInTree = (id, tree) => {
    let res = null
    for(let i=0;i<tree.length;i++) {
      let ele = tree[i]
      ele.id===id ? res = ele : ''
      if(res) break;
      if(ele.child.length) {
        res = getItemByIdInTree(id,ele.child)
      } 
    }
    return res
  }

  var list = [
    {id: '1',name: '手机号分配',child:[]},
    {id: '2',name: '账号密码分配',child:[
      {id: '2_1', name: '自动分配', child: []},
      {id: '2_2', name: '手动导入分配', child: []},
    ]},
  ]
  console.log(getItemByIdInTree('2_1', list));