js 递归遍历数组转成对应树形数组结构

[lizheng0515]

> 将entries 按照 level 转换成 result 数据结构

const entries = [
    {
        "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"
    }
];
	
const level = ["province", "city", "name"];

const  result = [
	{
		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'
					}
				]
			}
		]
	},
]

思路： 涉及到树形数组，采用递归遍历的方式

function transfrom(list, level) {
  const res = [];
  list.forEach(item => {
    pushItem(res, item, 0);
  });

  function pushItem(arr, obj, i) {
    const o = {
      value: obj[level[i]],
      children: [],
    };
    // 判断传入数组里是否有value等于要传入的项
    const hasItem = arr.find(el => el.value === obj[level[i]]);
    let nowArr;
    if(hasItem) {
      // 存在，则下一次遍历传入存在项的children
      nowArr = hasItem.children;
    }else{
      // 不存在 压入arr，下一次遍历传入此项的children
      arr.push(o);
      nowArr = o.children;
    }
    if(i === level.length - 1) delete o.children;
    i++;
    if(i < level.length) {
      // 递归进行层级的遍历
      pushItem(nowArr, obj, i);
    }
  }
}

transfrom(entries, level);