js 将线性数据转为树形的示例代码

在日常开发工作中，我们经常碰到将线性的数据转换成树的需求，今天给大家分享一个简单的转换算法。

数据结构

下面是我们转换前的数据：

[  {    "id":1,    "parent_id":0,    "name":"四川省"  },  {    "id":2,    "parent_id":0,    "name":"广东省"  },  {    "id":3,    "parent_id":0,    "name":"江西省"  },  {    "id":5,    "parent_id":1,    "name":"成都市"  },  {    "id":6,    "parent_id":5,    "name":"锦江区"  },  {    "id":7,    "parent_id":6,    "name":"九眼桥"  },  {    "id":8,    "parent_id":6,    "name":"兰桂坊"  },  {    "id":9,    "parent_id":2,    "name":"东莞市"  },  {    "id":10,    "parent_id":9,    "name":"长安镇"  },  {    "id":11,    "parent_id":3,    "name":"南昌市"  }]

我们转换后的结果是：

[  {    "id":1,    "parent_id":0,    "name":"四川省",    "children":[      {        "id":5,        "parent_id":1,        "name":"成都市",        "children":[          {            "id":6,            "parent_id":5,            "name":"锦江区",            "children":[              {                "id":7,                "parent_id":6,                "name":"九眼桥"              },              {                "id":8,                "parent_id":6,                "name":"兰桂坊"              }            ]          }        ]      }    ]  },  {    "id":2,    "parent_id":0,    "name":"广东省",    "children":[      {        "id":9,        "parent_id":2,        "name":"东莞市",        "children":[          {            "id":10,            "parent_id":9,            "name":"长安镇"          }        ]      }    ]  },  {    "id":3,    "parent_id":0,    "name":"江西省",    "children":[      {        "id":11,        "parent_id":3,        "name":"南昌市"      }    ]  }]

实现代码

let array = [  {    id: 1,    parent_id: 0,    name: "四川省"  },  {    id: 2,    parent_id: 0,    name: "广东省"  },  {    id: 3,    parent_id: 0,    name: "江西省"  },  {    id: 5,    parent_id: 1,    name: "成都市"  },  {    id: 6,    parent_id: 5,    name: "锦江区"  },  {    id: 7,    parent_id: 6,    name: "九眼桥"  },  {    id: 8,    parent_id: 6,    name: "兰桂坊"  },  {    id: 9,    parent_id: 2,    name: "东莞市"  },  {    id: 10,    parent_id: 9,    name: "长安镇"  },  {    id: 11,    parent_id: 3,    name: "南昌市"  }]function listToTree(list) {  let map = {};  list.forEach(item => {    if (! map[item.id]) {      map[item.id] = item;    }  });  list.forEach(item => {    if (item.parent_id !== 0) {      map[item.parent_id].children ? map[item.parent_id].children.push(item) : map[item.parent_id].children = [item];    }  });    return list.filter(item => {    if (item.parent_id === 0) {      return item;    }  })}console.log(listToTree(array));