我有类似的问题，几天前必须从平面数组显示文件夹树。我在TypeScript中没有看到任何解决方案，所以我希望它会有帮助。

在我的情况下，主父只有一个，rawData数组也不需要排序。解决方案基于准备临时对象 {parentId: [child1, child2，…]]}

示例原始数据

const flatData: any[] = Folder.ofCollection([
  {id: '1', title: 'some title' },
  {id: '2', title: 'some title', parentId: 1 },
  {id: '3', title: 'some title', parentId: 7 },
  {id: '4', title: 'some title', parentId: 1 },
  {id: '5', title: 'some title', parentId: 2 },
  {id: '6', title: 'some title', parentId: 5 },
  {id: '7', title: 'some title', parentId: 5 },

]);

文件夹的定义

export default class Folder {
    public static of(data: any): Folder {
        return new Folder(data);
    }

    public static ofCollection(objects: any[] = []): Folder[] {
        return objects.map((obj) => new Folder(obj));
    }

    public id: string;
    public parentId: string | null;
    public title: string;
    public children: Folder[];

    constructor(data: any = {}) {
        this.id = data.id;
        this.parentId = data.parentId || null;
        this.title = data.title;
        this.children = data.children || [];
    }
}

解决方案:返回扁平参数的树结构的函数

    public getTree(flatData: any[]): Folder[] {
        const addChildren = (item: Folder) => {
            item.children = tempChild[item.id] || [];
            if (item.children.length) {
                item.children.forEach((child: Folder) => {
                    addChildren(child);
                });
            }
        };

        const tempChild: any = {};
        flatData.forEach((item: Folder) => {
            const parentId = item.parentId || 0;
            Array.isArray(tempChild[parentId]) ? tempChild[parentId].push(item) : (tempChild[parentId] = [item]);
        });

        const tree: Folder[] = tempChild[0];
        tree.forEach((base: Folder) => {
            addChildren(base);
        });
        return tree;
    }

你可以使用npm包数组到树https://github.com/alferov/array-to-tree。 它将普通的节点数组(带有指向父节点的指针)转换为嵌套的数据结构。

解决了从数据库数据集检索到嵌套数据结构(即导航树)的转换问题。

用法:

var arrayToTree = require('array-to-tree');

var dataOne = [
  {
    id: 1,
    name: 'Portfolio',
    parent_id: undefined
  },
  {
    id: 2,
    name: 'Web Development',
    parent_id: 1
  },
  {
    id: 3,
    name: 'Recent Works',
    parent_id: 2
  },
  {
    id: 4,
    name: 'About Me',
    parent_id: undefined
  }
];

arrayToTree(dataOne);

/*
 * Output:
 *
 * Portfolio
 *   Web Development
 *     Recent Works
 * About Me
 */

ES6地图版本:

getTreeData = (items) => {
  if (items && items.length > 0) {
    const data = [];
    const map = {};
    items.map((item) => {
      const id = item.id; // custom id selector !!!
      if (!map.hasOwnProperty(id)) {
        // in case of duplicates
        map[id] = {
          ...item,
          children: [],
        };
      }
    });
    for (const id in map) {
      if (map.hasOwnProperty(id)) {
        let mappedElem = [];
        mappedElem = map[id];
        /// parentId : use custom id selector for parent
        if (
          mappedElem.parentId &&
          typeof map[mappedElem.parentId] !== "undefined"
        ) {
          map[mappedElem.parentId].children.push(mappedElem);
        } else {
          data.push(mappedElem);
        }
      }
    }
    return data;
  }
  return [];
};

/// use like this :

const treeData = getTreeData(flatList);

也可以使用lodashjs(v4.x)

function buildTree(arr){
  var a=_.keyBy(arr, 'id')
  return _
   .chain(arr)
   .groupBy('parentId')
   .forEach(function(v,k){ 
     k!='0' && (a[k].children=(a[k].children||[]).concat(v));
   })
   .result('0')
   .value();
}

(奖励1:节点可以排序，也可以不排序)

(bonus2:不需要第三方库，纯js)

(BONUS3:用户“Elias Rabl”说这是最高效的解决方案，见下面他的回答)

下面就是:

const createDataTree = dataset => {
  const hashTable = Object.create(null);
  dataset.forEach(aData => hashTable[aData.ID] = {...aData, childNodes: []});
  const dataTree = [];
  dataset.forEach(aData => {
    if(aData.parentID) hashTable[aData.parentID].childNodes.push(hashTable[aData.ID])
    else dataTree.push(hashTable[aData.ID])
  });
  return dataTree;
};

下面是一个测试，它可能会帮助你理解解决方案是如何工作的:

it('creates a correct shape of dataTree', () => {
  const dataSet = [{
    "ID": 1,
    "Phone": "(403) 125-2552",
    "City": "Coevorden",
    "Name": "Grady"
  }, {
    "ID": 2,
    "parentID": 1,
    "Phone": "(979) 486-1932",
    "City": "Chełm",
    "Name": "Scarlet"
  }];

  const expectedDataTree = [{
    "ID": 1,
    "Phone": "(403) 125-2552",
    "City": "Coevorden",
    "Name": "Grady",
    childNodes: [{
      "ID": 2,
      "parentID": 1,
      "Phone": "(979) 486-1932",
      "City": "Chełm",
      "Name": "Scarlet",
      childNodes : []
    }]
  }];

  expect(createDataTree(dataSet)).toEqual(expectedDataTree);
});

将节点数组转换为树

ES6函数转换数组节点(由父ID相关)到树结构:

/**
 * Convert nodes list related by parent ID - to tree.
 * @syntax getTree(nodesArray [, rootID [, propertyName]])
 *
 * @param {Array} arr   Array of nodes
 * @param {integer} id  Defaults to 0
 * @param {string} p    Property name. Defaults to "parent_id"
 * @returns {Object}    Nodes tree
 */

const getTree = (arr, p = "parent_id") => arr.reduce((o, n) => {

  if (!o[n.id]) o[n.id] = {};
  if (!o[n[p]]) o[n[p]] = {};
  if (!o[n[p]].nodes) o[n[p]].nodes= [];
  if (o[n.id].nodes) n.nodes= o[n.id].nodes;

  o[n[p]].nodes.push(n);
  o[n.id] = n;

  return o;
}, {});

从节点树生成HTML列表

有了我们的树，这里有一个递归函数来构建UL > LI元素:

/**
 * Convert Tree structure to UL>LI and append to Element
 * @syntax getTree(treeArray [, TargetElement [, onLICreatedCallback ]])
 *
 * @param {Array} tree Tree array of nodes
 * @param {Element} el HTMLElement to insert into
 * @param {function} cb Callback function called on every LI creation
 */

const treeToHTML = (tree, el, cb) => el.append(tree.reduce((ul, n) => {
  const li = document.createElement('li');

  if (cb) cb.call(li, n);
  if (n.nodes?.length) treeToHTML(n.nodes, li, cb);

  ul.append(li);
  return ul;
}, document.createElement('ul')));

演示时间

下面是一个使用上述两个函数的线性节点数组的例子:

const getTree = (arr, p = "parent_id") => arr.reduce((o, n) => { if (!o[n.id]) o[n.id] = {}; if (!o[n[p]]) o[n[p]] = {}; if (!o[n[p]].nodes) o[n[p]].nodes = []; if (o[n.id].nodes) n.nodes = o[n.id].nodes; o[n[p]].nodes.push(n); o[n.id] = n; return o; }, {}); const treeToHTML = (tree, el, cb) => el.append(tree.reduce((ul, n) => { const li = document.createElement('li'); if (cb) cb.call(li, n); if (n.nodes?.length) treeToHTML(n.nodes, li, cb); ul.append(li); return ul; }, document.createElement('ul'))); // DEMO TIME: const nodesList = [ {id: 10, parent_id: 4, text: "Item 10"}, // PS: Order does not matters {id: 1, parent_id: 0, text: "Item 1"}, {id: 4, parent_id: 0, text: "Item 4"}, {id: 3, parent_id: 5, text: "Item 3"}, {id: 5, parent_id: 4, text: "Item 5"}, {id: 2, parent_id: 1, text: "Item 2"}, ]; const myTree = getTree(nodesList)[0].nodes; // Get nodes of Root (0) treeToHTML(myTree, document.querySelector("#tree"), function(node) { this.textContent = `(${node.parent_id} ${node.id}) ${node.text}`; this._node = node; this.addEventListener('click', clickHandler); }); function clickHandler(ev) { if (ev.target !== this) return; console.clear(); console.log(this._node.id); }; <div id="tree"></div>