使用ES6方法。工作很有魅力

//数据集 //一个顶级注释 Const注释= [{ id: 1、 parent_id:零 }, { id: 2 parent_id: 1 }, { id: 3, parent_id: 1 }, { id: 4 parent_id: 2 }, { id: 5 parent_id: 4 }); Const nest = (items, id = null, link = 'parent_id') => 项目 .filter(item => item[link] === id) .map(item =>({…Item, children: nest(items, Item .id)})); console.log ( 巢(评论) ）

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();
}

更新2022

这是一个针对无序项的建议。该函数使用单个循环和哈希表，并收集所有带有id的项。如果找到根节点，则将该对象添加到结果数组中。

const getTree = (data, root) => { const t = {}; data.forEach(o => ((t[o.parentId] ??= {}).children ??= []).push(Object.assign(t[o.id] ??= {}, o))); return t[root].children; }, data = { People: [{ id: "12", parentId: "0", text: "Man", level: "1", children: null }, { id: "6", parentId: "12", text: "Boy", level: "2", children: null }, { id: "7", parentId: "12", text: "Other", level: "2", children: null }, { id: "9", parentId: "0", text: "Woman", level: "1", children: null }, { id: "11", parentId: "9", text: "Girl", level: "2", children: null }], Animals: [{ id: "5", parentId: "0", text: "Dog", level: "1", children: null }, { id: "8", parentId: "5", text: "Puppy", level: "2", children: null }, { id: "10", parentId: "13", text: "Cat", level: "1", children: null }, { id: "14", parentId: "13", text: "Kitten", level: "2", children: null }] }, result = Object.fromEntries(Object .entries(data) .map(([k, v]) => [k, getTree(v, '0')]) ); console.log(result); .as-console-wrapper { max-height: 100% !important; top: 0; }

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
 */

如果使用地图查找，就有一个有效的解决方案。如果父母总是在他们的孩子之前，你可以合并两个for循环。它支持多个根。它在悬垂的分支上给出一个错误，但可以修改为忽略它们。它不需要第三方库。就我所知，这是最快的解决方法。

function list_to_tree(list) { var map = {}, node, roots = [], i; for (i = 0; i < list.length; i += 1) { map[list[i].id] = i; // initialize the map list[i].children = []; // initialize the children } for (i = 0; i < list.length; i += 1) { node = list[i]; if (node.parentId !== "0") { // if you have dangling branches check that map[node.parentId] exists list[map[node.parentId]].children.push(node); } else { roots.push(node); } } return roots; } var entries = [{ "id": "12", "parentId": "0", "text": "Man", "level": "1", "children": null }, { "id": "6", "parentId": "12", "text": "Boy", "level": "2", "children": null }, { "id": "7", "parentId": "12", "text": "Other", "level": "2", "children": null }, { "id": "9", "parentId": "0", "text": "Woman", "level": "1", "children": null }, { "id": "11", "parentId": "9", "text": "Girl", "level": "2", "children": null } ]; console.log(list_to_tree(entries));

如果你喜欢复杂性理论，这个解决方案是Θ(n log(n))。递归过滤器的解决方案是Θ(n^2)，这对于大型数据集可能是一个问题。

下面是Steven Harris的一个修改版本，它是普通的ES5，返回一个以id为键的对象，而不是返回顶层和子层的节点数组。

unflattenToObject = function(array, parent) {
  var tree = {};
  parent = typeof parent !== 'undefined' ? parent : {id: 0};

  var childrenArray = array.filter(function(child) {
    return child.parentid == parent.id;
  });

  if (childrenArray.length > 0) {
    var childrenObject = {};
    // Transform children into a hash/object keyed on token
    childrenArray.forEach(function(child) {
      childrenObject[child.id] = child;
    });
    if (parent.id == 0) {
      tree = childrenObject;
    } else {
      parent['children'] = childrenObject;
    }
    childrenArray.forEach(function(child) {
      unflattenToObject(array, child);
    })
  }

  return tree;
};

var arr = [
    {'id':1 ,'parentid': 0},
    {'id':2 ,'parentid': 1},
    {'id':3 ,'parentid': 1},
    {'id':4 ,'parentid': 2},
    {'id':5 ,'parentid': 0},
    {'id':6 ,'parentid': 0},
    {'id':7 ,'parentid': 4}
];
tree = unflattenToObject(arr);