具有多個頂級父級和索引的反向嵌套樹

我有以下資料結構

[
  {
    id: 1,
    name: 'Top Level Topic 1',
    parentTopic: undefined
  },
  {
    id: 2,
    name: 'Some topic internally',
    parentTopic: 1
  },
  {
    id: 3,
    name: 'Another topic',
    parentTopic: 2
  },
  { id: 4, name: 'Just another topic', parentTopic: 2 },
  {
    id: 5,
    name: 'Another topic',
    parentTopic: 1
  },
  {
    id: 6,
    name: 'Another topic',
    parentTopic: 5
  },
  {
    id: 7,
    name: 'Another topic',
    parentTopic: 5
  },
  { id: 8, name: 'Another topic', parentTopic: 1 },
  {
    id: 9,
    name: 'Another topic',
    parentTopic: 8
  },
  {
    id: 10,
    name: 'Another topic',
    parentTopic: 9
  },
  {
    id: 11,
    name: 'Another topic',
    parentTopic: 10
  },
  {
    id: 12,
    name: 'Another Top Level Topic',
    parentTopic: undefined
  },
  { id: 13, name: 'Another Important Topic', parentTopic: 12 }]

我正在嘗試以下列方式轉換和構建它

[
  {
    id: 1,
    name: 'Top Level Topic 1',
    parentTopic: undefined,
    index: 1,
    children: [
      {
        id: 2,
        name: 'Some topic internally',
        parentTopic: 1,
        index: 1.1,
        children: [
          {
            id: 3,
            name: 'Another topic',
            parentTopic: 2,
            index: 1.1.1,
            children: []
          },
          {
            id: 4,
            name: 'Just another topic',
            parentTopic: 2,
            index: 1.1.2,
            children: []
          },
        ]
      },
      {
        id: 5,
        name: 'Another topic',
        parentTopic: 1,
        index: 1.2,
        children: [
          {
            id: 6,
            name: 'Another topic',
            parentTopic: 5,
            index: 1.2.1,
            children: []
          },
          {
            id: 7,
            name: 'Another topic',
            parentTopic: 5,
            index: 1.2.2,
            children: []
          },
        ]
      },
      {
        id: 8,
        name: 'Another topic',
        parentTopic: 1,
        index: 1.3,
        children: [
            {
              id: 9,
              name: 'Another topic',
              parentTopic: 8,
              index: 1.3.1,
              children: [
                {
                  id: 10,
                  name: 'Another topic',
                  parentTopic: 9,
                  index: 1.3.1.1,
                  children: []
                },
              ]
            },
        ]
      },
    ]
  },
  {
    id: 12,
    name: 'Another Top Level Topic',
    parentTopic: undefined,
    index: 2
    children: [
      {
        id: 13,
        name: 'Another Important Topic',
        parentTopic: 12,
        index: 2.1,
        children: []
      },
    ]
  },
]

我的挑戰是我不確定如何遞回執行此操作。同樣在輸出中，您會注意到一個索引，它可以很好地在迭代時生成，或者它可能只是來自資料庫，這意味著我的原始資料結構已經有了它。

如果有人可以幫助我，我將不勝感激:)

這是我的代碼，但在頂層它是一個字典而不是字典串列

    const invertHierarchy = (arr) => {
      const map = {};
      let root;
      for (const ele of arr) {
        map[ele.id] = ele;
        ele.topics = [];
      }
      for (const ele of arr) {
        if (map[ele.parentTopic] != null) map[ele.parentTopic].topics.push(ele);
        else root = ele;
      }
      return root;
    };

uj5u.com熱心網友回復：

const data = [{"id":1,"name":"Top Level Topic 1"},{"id":2,"name":"Some topic internally","parentTopic":1},{"id":3,"name":"Another topic","parentTopic":2},{"id":4,"name":"Just another topic","parentTopic":2},{"id":5,"name":"Another topic","parentTopic":1},{"id":6,"name":"Another topic","parentTopic":5},{"id":7,"name":"Another topic","parentTopic":5},{"id":8,"name":"Another topic","parentTopic":1},{"id":9,"name":"Another topic","parentTopic":8},{"id":10,"name":"Another topic","parentTopic":9},{"id":11,"name":"Another topic","parentTopic":10},{"id":12,"name":"Another Top Level Topic"},{"id":13,"name":"Another Important Topic","parentTopic":12}];

const getPrefix = (prefix, i) => prefix ? `${prefix}.${i 1}` : `${i 1}`

const f = (arr, parentTopic, prefix) =>
  arr.filter(e=>e.parentTopic===parentTopic).map((e,i)=>({
    ...e,
    index: getPrefix(prefix,i),
    children: f(arr, e.id, getPrefix(prefix,i))
}))

console.log(f(data))

uj5u.com熱心網友回復：

您可以采用另一種方法，將所有節點及其父節點存盤在一個物件中，并只采用沒有父節點的陣列作為結果。

通過使用單個回圈，它還可以動態構建索引。

const
    data = [{ id: 1, name: 'Top Level Topic 1', parentTopic: undefined }, { id: 2, name: 'Some topic internally', parentTopic: 1 }, { id: 3, name: 'Another topic', parentTopic: 2 }, { id: 4, name: 'Just another topic', parentTopic: 2 }, { id: 5, name: 'Another topic', parentTopic: 1 }, { id: 6, name: 'Another topic', parentTopic: 5 }, { id: 7, name: 'Another topic', parentTopic: 5 }, { id: 8, name: 'Another topic', parentTopic: 1 }, { id: 9, name: 'Another topic', parentTopic: 8 }, { id: 10, name: 'Another topic', parentTopic: 9 }, { id: 11, name: 'Another topic', parentTopic: 10 }, { id: 12, name: 'Another Top Level Topic', parentTopic: undefined }, { id: 13, name: 'Another Important Topic', parentTopic: 12 }],
    tree = function(data, root) {
        const t = {};
        data.forEach(o => {
            Object.assign(t[o.id] ??= {}, { ...o });
            ((t[o.parentTopic] ??= {}).children ??= []).push(t[o.id]);
            const index = t[o.parentTopic].index || '';
            t[o.id].index = index   (index && '.')   t[o.parentTopic].children.length;
        });
        return t[root].children;
    }(data, undefined);

console.log(tree);

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