扁平数据整理为树结构算法

将如下扁平对象，转为树形对象。parent字段为空字符串的节点为根节点：

var input = {
  h3: {
    parent: 'h2',
    name: '副总经理(市场)'
  },
  h1: {
    parent: 'h0',
    name: '公司机构'
  },
  h7: {
    parent: 'h6',
    name: '副总经理(总务)'
  },
  h4: {
    parent: 'h3',
    name: '销售经理'
  },
  h2: {
    parent: 'h1',
    name: '总经理'
  },
  h8: {
    parent: 'h0',
    name: '财务总监'
  },
  h6: {
    parent: 'h4',
    name: '仓管总监'
  },
  h5: {
    parent: 'h4',
    name: '销售代表'
  },
  h0: {
    parent: '',
    name: 'root'
  }
};

var plain2Tree = function (obj) {
  var key, res
  for(key in obj) {
    var parent = obj[key].parent
    if(parent === '') {
      res = obj[key]
    } else {
      obj[parent][key] = obj[key]
    }
  }
  return res
}

下列数据整理成级联选择数据：

最终数据：

var data = [{
  "value": "浙江",
  "children": [{
    "value": "杭州",
    "children": [{
      "value": "西湖"
    }]
  }]
}, {
  "value": "四川",
  "children": [{
    "value": "成都",
    "children": [{
      "value": "锦里"
    }, {
      "value": "方所"
    }]
  }, {
    "value": "阿坝",
    "children": [{
      "value": "九寨沟"
    }]
  }]
}]

原始数据： 

var data = [{
  "province": "浙江",
  "city": "杭州",
  "name": "西湖"
}, {
  "province": "四川",
  "city": "成都",
  "name": "锦里"
}, {
  "province": "四川",
  "city": "成都",
  "name": "方所"
}, {
  "province": "四川",
  "city": "阿坝",
  "name": "九寨沟"
}]

var transObject = function(tableData, keys) {
  let hashTable = {}, res = []
  for (let i = 0; i < tableData.length; i++) {
    let arr = res, cur = hashTable
    for (let j = 0; j < keys.length; j++) {
      let key = keys[j], filed = tableData[i][key]
      if (!cur[filed]) {
        let pusher = {
          value: filed
        }, tmp
        if (j !== (keys.length - 1)) {
          tmp = []
          pusher.children = tmp
        }
        cur[filed] = { $$pos: arr.push(pusher) - 1 }
        cur = cur[filed]
        arr = tmp
      } else {
        cur = cur[filed]
        arr = arr[cur.$$pos].children
      }
    }
  }
  return res
}