javascript - 使用 Javascript ECMAScript 6 将表数据转换为分层树数据的算法

Question

我有一个 JSON 表数据，想要转换为 JSON 树数据，如下所示。我正在使用任何新的 ECMAScript 6 运算符或具有函数式方法的语句(不是通过 ES5 的标准递归算法)在 JavaScript 中寻找一种有效的算法？

表格数据:

[
   {
      "Children":"4th Grand Father"
   },
   {
      "Name":"4th Grand Father",
      "Children":"3rd Grand Father"
   },
   {
      "Name":"3rd Grand Father",
      "Children":"2nd Grand Father"
   },
   {
      "Name":"2nd Grand Father",
      "Children":"Grand Father"
   },
   {
      "Name":"Grand Father",
      "Children":"Father"
   },
   {
      "Name":"Grand Father",
      "Children":"Uncle"
   },
   {
      "Name":"Uncle",
      "Children":"Cousin"
   },
   {
      "Name":"Father",
      "Children":"Brother"
   },
   {
      "Name":"Father",
      "Children":"Me"
   }
]

树数据:

[
  {
    "Name": "4th Grand Father",
    "Children": [
      {
        "Name": "3rd Grand Father",
        "Children": [
          {
            "Name": "2nd Grand Father",
            "Children": [
              {
                "Name": "Grand Father",
                "Children": [
                  {
                    "Name": "Father",
                    "children": [
                      {
                        "Name": "Brother"
                      },
                      {
                        "Name": "Me"
                      }
                    ]
                  },
                  {
                    "Name": "Uncle",
                    "children": [
                      {
                        "Name": "Cousin"
                      }
                    ]
                  }
                ]
              }
            ]
          }
        ]
      }
    ]
  }
]

Answer 1

您可以使用这个 ES6 函数，它使用 Map、箭头函数、解构参数赋值。您甚至可以用扩展语法替换 concat 调用，但我认为这不会带来任何好处:

const makeTree = (data) => {
    const hash = data.reduce ( (acc, {Name, Children}) => 
        acc.set(Name, (acc.get(Name) || []).concat(Children)) 
    , new Map );

    const recurse = (Name) => hash.has(Name)
            ?   { Name, Children: hash.get(Name).map(recurse) }
            :   { Name };
    return recurse(undefined).Children;
}

// Sample data
const data = [
   {
      "Children":"4th Grand Father"
   },
   {
      "Name":"4th Grand Father",
      "Children":"3rd Grand Father"
   },
   {
      "Name":"3rd Grand Father",
      "Children":"2nd Grand Father"
   },
   {
      "Name":"2nd Grand Father",
      "Children":"Grand Father"
   },
   {
      "Name":"Grand Father",
      "Children":"Father"
   },
   {
      "Name":"Grand Father",
      "Children":"Uncle"
   },
   {
      "Name":"Uncle",
      "Children":"Cousin"
   },
   {
      "Name":"Father",
      "Children":"Brother"
   },
   {
      "Name":"Father",
      "Children":"Me"
   }
];

const result = makeTree(data);

console.log(result);

.as-console-wrapper { max-height: 100% !important; top: 0; }

说明:

hash 变量是从一个空的 Map 构建的，将记录添加到由 Name 键控的变量中。链接到每个键的值是子信息，作为数组。当遇到相同的 Name 时(即 acc.get(Name) 返回一些东西)， child 被添加到已经存在的数组中，否则 (|| [ ]) 创建一个空数组并将子项添加到该数组中。

一旦 hash 完成，层次结构的顶部由其缺失的 Name(undefined)获取，并通过递归子级在哈希中查找并添加到最终对象。

由于结果对象是一个具有Children 数组的对象，而所需的结果实际上就是该数组，因此返回的是Children 属性。 p>