在javascript中从平面数组构建树数组
Build tree array from flat array in javascript
我有一个复杂的json文件,我必须用javascript处理它以使其分层,以便以后构建树。json 的每个条目都有:ID :唯一 ID,parentId :父节点的 id(如果节点是树的根,则为 0(级别:树中的深度级别
json 数据已"排序"。我的意思是,一个条目在自身之上有一个父节点或兄弟节点,在它自己下面有一个子节点或兄弟节点。
输入:
{
"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
},
]
}
预期输出 :
{
"People": [
{
"id": "12",
"parentId": "0",
"text": "Man",
"level": "1",
"children": [
{
"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":
{
"id": "11",
"parentId": "9",
"text": "Girl",
"level": "2",
"children": null
}
}
],
"Animals": [
{
"id": "5",
"parentId": "0",
"text": "Dog",
"level": "1",
"children":
{
"id": "8",
"parentId": "5",
"text": "Puppy",
"level": "2",
"children": null
}
},
{
"id": "10",
"parentId": "13",
"text": "Cat",
"level": "1",
"children":
{
"id": "14",
"parentId": "13",
"text": "Kitten",
"level": "2",
"children": null
}
}
]
}
如果您使用地图查找,则有一个有效的解决方案。如果父母总是先于他们的孩子,你可以合并两个for循环。它支持多个根。它在悬垂的树枝上给出错误,但可以修改以忽略它们。它不需要第 3 方库。据我所知,这是最快的解决方案。
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((。递归过滤器解决方案是 Θ(n^2(,这对于大型数据集来说可能是一个问题。
( 奖励 1 : 节点可能会或可能不会被订购(
(奖励2:不需要第三方库,纯JS(
( 奖励3 : 用户"Elias Rabl"说这是性能最高的解决方案,请参阅下面的答案(
在这里:
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;
};
这是一个测试,它可能会帮助您了解解决方案的工作原理:
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);
});
正如@Sander所提到的,@Halcyon的答案假设一个预排序的数组,以下不是。 (但是,它确实假设您已经加载了下划线.js - 尽管它可以用香草javascript编写(:
法典
// Example usage
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}
];
unflatten = function( array, parent, tree ){
tree = typeof tree !== 'undefined' ? tree : [];
parent = typeof parent !== 'undefined' ? parent : { id: 0 };
var children = _.filter( array, function(child){ return child.parentid == parent.id; });
if( !_.isEmpty( children ) ){
if( parent.id == 0 ){
tree = children;
}else{
parent['children'] = children
}
_.each( children, function( child ){ unflatten( array, child ) } );
}
return tree;
}
tree = unflatten( arr );
document.body.innerHTML = "<pre>" + (JSON.stringify(tree, null, " "))
<script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.9.1/underscore-min.js"></script>
要求
它假定属性"id"和"parentid"分别表示ID和父ID。必须有父 ID 为 0 的元素,否则你会得到一个空数组。孤儿元素及其后代"丢失"
http://jsfiddle.net/LkkwH/1/
使用这种 ES6 方法。像魅力一样工作
// Data Set
// One top level comment
const comments = [{
id: 1,
parent_id: null
}, {
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') =>
items
.filter(item => item[link] === id)
.map(item => ({ ...item, children: nest(items, item.id) }));
console.log(
nest(comments)
)
有同样的问题,但我无法确定数据是否已排序。我无法使用第三方库,所以这只是香草 Js;输入数据可以从@Stephen的例子中获取;
var arr = [
{'id':1 ,'parentid' : 0},
{'id':4 ,'parentid' : 2},
{'id':3 ,'parentid' : 1},
{'id':5 ,'parentid' : 0},
{'id':6 ,'parentid' : 0},
{'id':2 ,'parentid' : 1},
{'id':7 ,'parentid' : 4},
{'id':8 ,'parentid' : 1}
];
function unflatten(arr) {
var tree = [],
mappedArr = {},
arrElem,
mappedElem;
// First map the nodes of the array to an object -> create a hash table.
for(var i = 0, len = arr.length; i < len; i++) {
arrElem = arr[i];
mappedArr[arrElem.id] = arrElem;
mappedArr[arrElem.id]['children'] = [];
}
for (var id in mappedArr) {
if (mappedArr.hasOwnProperty(id)) {
mappedElem = mappedArr[id];
// If the element is not at the root level, add it to its parent array of children.
if (mappedElem.parentid) {
mappedArr[mappedElem['parentid']]['children'].push(mappedElem);
}
// If the element is at the root level, add it to first level elements array.
else {
tree.push(mappedElem);
}
}
}
return tree;
}
var tree = unflatten(arr);
document.body.innerHTML = "<pre>" + (JSON.stringify(tree, null, " "))
JS小提琴
平面数组到树
一个更简单的函数list-to-tree-lite
npm install list-to-tree-lite
listToTree(list)
源:
function listToTree(data, options) {
options = options || {};
var ID_KEY = options.idKey || 'id';
var PARENT_KEY = options.parentKey || 'parent';
var CHILDREN_KEY = options.childrenKey || 'children';
var tree = [],
childrenOf = {};
var item, id, parentId;
for (var i = 0, length = data.length; i < length; i++) {
item = data[i];
id = item[ID_KEY];
parentId = item[PARENT_KEY] || 0;
// every item may have children
childrenOf[id] = childrenOf[id] || [];
// init its children
item[CHILDREN_KEY] = childrenOf[id];
if (parentId != 0) {
// init its parent's children object
childrenOf[parentId] = childrenOf[parentId] || [];
// push it into its parent's children object
childrenOf[parentId].push(item);
} else {
tree.push(item);
}
};
return tree;
}
斯菲德尔
您只需两行编码即可处理此问题:
_(flatArray).forEach(f=>
{f.nodes=_(flatArray).filter(g=>g.parentId==f.id).value();});
var resultArray=_(flatArray).filter(f=>f.parentId==null).value();
在线测试(请参阅浏览器控制台以获取创建的树(
要求:
1-安装 lodash 4(一个 Javascript 库,用于使用高性能方法 => 操作对象和集合,如 c# 中的 Linq( Lodash
2-如下所示的平面阵列:
var flatArray=
[{
id:1,parentId:null,text:"parent1",nodes:[]
}
,{
id:2,parentId:null,text:"parent2",nodes:[]
}
,
{
id:3,parentId:1,text:"childId3Parent1",nodes:[]
}
,
{
id:4,parentId:1,text:"childId4Parent1",nodes:[]
}
,
{
id:5,parentId:2,text:"childId5Parent2",nodes:[]
}
,
{
id:6,parentId:2,text:"childId6Parent2",nodes:[]
}
,
{
id:7,parentId:3,text:"childId7Parent3",nodes:[]
}
,
{
id:8,parentId:5,text:"childId8Parent5",nodes:[]
}];
感谢巴赫沙巴迪先生
祝你好运
很有用 包列表到树安装:
bower install list-to-tree --save
或
npm install list-to-tree --save
例如,有列表:
var list = [
{
id: 1,
parent: 0
}, {
id: 2,
parent: 1
}, {
id: 3,
parent: 1
}, {
id: 4,
parent: 2
}, {
id: 5,
parent: 2
}, {
id: 6,
parent: 0
}, {
id: 7,
parent: 0
}, {
id: 8,
parent: 7
}, {
id: 9,
parent: 8
}, {
id: 10,
parent: 0
}
];
使用包列表到树:
var ltt = new LTT(list, {
key_id: 'id',
key_parent: 'parent'
});
var tree = ltt.GetTree();
结果:
[{
"id": 1,
"parent": 0,
"child": [
{
"id": 2,
"parent": 1,
"child": [
{
"id": 4,
"parent": 2
}, {
"id": 5, "parent": 2
}
]
},
{
"id": 3,
"parent": 1
}
]
}, {
"id": 6,
"parent": 0
}, {
"id": 7,
"parent": 0,
"child": [
{
"id": 8,
"parent": 7,
"child": [
{
"id": 9,
"parent": 8
}
]
}
]
}, {
"id": 10,
"parent": 0
}];
我编写了一个测试脚本来评估由用户shekhardtu(见答案(和FurkanO(见答案(提出的两个最通用解决方案的性能(这意味着输入不必事先排序,代码不依赖于第三方库(。
http://playcode.io/316025?tabs=console&script.js&output
FurkanO的解决方案似乎是最快的。
/*
** performance test for https://stackoverflow.com/questions/18017869/build-tree-array-from-flat-array-in-javascript
*/
// Data Set (e.g. nested comments)
var comments = [{
id: 1,
parent_id: null
}, {
id: 2,
parent_id: 1
}, {
id: 3,
parent_id: 4
}, {
id: 4,
parent_id: null
}, {
id: 5,
parent_id: 4
}];
// add some random entries
let maxParentId = 10000;
for (let i=6; i<=maxParentId; i++)
{
let randVal = Math.floor((Math.random() * maxParentId) + 1);
comments.push({
id: i,
parent_id: (randVal % 200 === 0 ? null : randVal)
});
}
// solution from user "shekhardtu" (https://stackoverflow.com/a/55241491/5135171)
const nest = (items, id = null, link = 'parent_id') =>
items
.filter(item => item[link] === id)
.map(item => ({ ...item, children: nest(items, item.id) }));
;
// solution from user "FurkanO" (https://stackoverflow.com/a/40732240/5135171)
const createDataTree = dataset => {
let hashTable = Object.create(null)
dataset.forEach( aData => hashTable[aData.id] = { ...aData, children : [] } )
let dataTree = []
dataset.forEach( aData => {
if( aData.parent_id ) hashTable[aData.parent_id].children.push(hashTable[aData.id])
else dataTree.push(hashTable[aData.id])
} )
return dataTree
};
/*
** lets evaluate the timing for both methods
*/
let t0 = performance.now();
let createDataTreeResult = createDataTree(comments);
let t1 = performance.now();
console.log("Call to createDataTree took " + Math.floor(t1 - t0) + " milliseconds.");
t0 = performance.now();
let nestResult = nest(comments);
t1 = performance.now();
console.log("Call to nest took " + Math.floor(t1 - t0) + " milliseconds.");
//console.log(nestResult);
//console.log(createDataTreeResult);
// bad, but simple way of comparing object equality
console.log(JSON.stringify(nestResult)===JSON.stringify(createDataTreeResult));
经过多次尝试,我想出了这个:
const arrayToTree = (arr, parent = 0) => arr .filter(item => item.parent === parent).map(child => ({ ...child, children: arrayToTree(arr, child.index) }));
const entries = [
{
index: 1,
parent: 0
},
{
index: 2,
parent: 1
},
{
index: 3,
parent: 2
},
{
index: 4,
parent: 2
},
{
index: 5,
parent: 4
},
{
index: 6,
parent: 5
},
{
index: 7,
parent: 6
},
{
index: 8,
parent: 7
},
{
index: 9,
parent: 8
},
{
index: 10,
parent: 9
},
{
index: 11,
parent: 7
},
{
index: 13,
parent: 11
},
{
index: 12,
parent: 0
}
];
const arrayToTree = (arr, parent = 0) => arr .filter(item => item.parent === parent) .map(child => ({ ...child, children: arrayToTree(arr, child.index) })); console.log(arrayToTree(entries));
2022 年更新
这是针对无序项目的建议。此函数与单个循环和哈希表一起使用,并收集所有项目及其id
。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; }
将节点数组转换为树
ES6 函数将节点数组(由父 ID 相关( - 转换为树结构:
/**
* 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
下面是一个具有线性节点数组并使用上述两个函数的示例:
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>
我喜欢@WilliamLeung的纯JavaScript解决方案,但有时您需要在现有数组中进行更改以保留对对象的引用。
function listToTree(data, options) {
options = options || {};
var ID_KEY = options.idKey || 'id';
var PARENT_KEY = options.parentKey || 'parent';
var CHILDREN_KEY = options.childrenKey || 'children';
var item, id, parentId;
var map = {};
for(var i = 0; i < data.length; i++ ) { // make cache
if(data[i][ID_KEY]){
map[data[i][ID_KEY]] = data[i];
data[i][CHILDREN_KEY] = [];
}
}
for (var i = 0; i < data.length; i++) {
if(data[i][PARENT_KEY]) { // is a child
if(map[data[i][PARENT_KEY]]) // for dirty data
{
map[data[i][PARENT_KEY]][CHILDREN_KEY].push(data[i]); // add child to parent
data.splice( i, 1 ); // remove from root
i--; // iterator correction
} else {
data[i][PARENT_KEY] = 0; // clean dirty data
}
}
};
return data;
}
示例:https://jsfiddle.net/kqw1qsf0/17/
数组元素可以处于混乱顺序
let array = [
{ id: 1, data: 'something', parent_id: null, children: [] },
{ id: 2, data: 'something', parent_id: 1, children: [] },
{ id: 5, data: 'something', parent_id: 4, children: [] },
{ id: 4, data: 'something', parent_id: 3, children: [] },
{ id: 3, data: 'something', parent_id: null, children: [] },
{ id: 6, data: 'something', parent_id: null, children: [] }
]
function buildTree(array) {
let tree = []
for (let i = 0; i < array.length; i++) {
if (array[i].parent_id) {
let parent = array.filter(elem => elem.id === array[i].parent_id).pop()
parent.children.push(array[i])
} else {
tree.push(array[i])
}
}
return tree
}
const tree = buildTree(array)
console.log(tree);
.as-console-wrapper { min-height: 100% }
var data = [{"country":"india","gender":"male","type":"lower","class":"X"},
{"country":"china","gender":"female","type":"upper"},
{"country":"india","gender":"female","type":"lower"},
{"country":"india","gender":"female","type":"upper"}];
var seq = ["country","type","gender","class"];
var treeData = createHieArr(data,seq);
console.log(treeData)
function createHieArr(data,seq){
var hieObj = createHieobj(data,seq,0),
hieArr = convertToHieArr(hieObj,"Top Level");
return [{"name": "Top Level", "parent": "null",
"children" : hieArr}]
function convertToHieArr(eachObj,parent){
var arr = [];
for(var i in eachObj){
arr.push({"name":i,"parent":parent,"children":convertToHieArr(eachObj[i],i)})
}
return arr;
}
function createHieobj(data,seq,ind){
var s = seq[ind];
if(s == undefined){
return [];
}
var childObj = {};
for(var ele of data){
if(ele[s] != undefined){
if(childObj[ele[s]] == undefined){
childObj[ele[s]] = [];
}
childObj[ele[s]].push(ele);
}
}
ind = ind+1;
for(var ch in childObj){
childObj[ch] = createHieobj(childObj[ch],seq,ind)
}
return childObj;
}
}
这是我在 react 项目中使用的
// ListToTree.js
import _filter from 'lodash/filter';
import _map from 'lodash/map';
export default (arr, parentIdKey) => _map(_filter(arr, ar => !ar[parentIdKey]), ar => ({
...ar,
children: _filter(arr, { [parentIdKey]: ar.id }),
}));
用法:
// somewhere.js
import ListToTree from '../Transforms/ListToTree';
const arr = [
{
"id":"Bci6XhCLZKPXZMUztm1R",
"name":"Sith"
},
{
"id":"C3D71CMmASiR6FfDPlEy",
"name":"Luke",
"parentCategoryId":"ltatOlEkHdVPf49ACCMc"
},
{
"id":"aS8Ag1BQqxkO6iWBFnsf",
"name":"Obi Wan",
"parentCategoryId":"ltatOlEkHdVPf49ACCMc"
},
{
"id":"ltatOlEkHdVPf49ACCMc",
"name":"Jedi"
},
{
"id":"pw3CNdNhnbuxhPar6nOP",
"name":"Palpatine",
"parentCategoryId":"Bci6XhCLZKPXZMUztm1R"
}
];
const response = ListToTree(arr, 'parentCategoryId');
输出:
[
{
"id":"Bci6XhCLZKPXZMUztm1R",
"name":"Sith",
"children":[
{
"id":"pw3CNdNhnbuxhPar6nOP",
"name":"Palpatine",
"parentCategoryId":"Bci6XhCLZKPXZMUztm1R"
}
]
},
{
"id":"ltatOlEkHdVPf49ACCMc",
"name":"Jedi",
"children":[
{
"id":"C3D71CMmASiR6FfDPlEy",
"name":"Luke",
"parentCategoryId":"ltatOlEkHdVPf49ACCMc"
},
{
"id":"aS8Ag1BQqxkO6iWBFnsf",
"name":"Obi Wan",
"parentCategoryId":"ltatOlEkHdVPf49ACCMc"
}
]
}
]```
前我遇到了类似的问题,当时必须显示平面数组中的文件夹树。我在这里没有看到 TypeScript 中的任何解决方案,所以我希望它会有所帮助。
在我的情况下,主父级只有一个,原始数据数组也不必排序。基于准备临时对象的解决方案 {parentId: [child1, child2, ...] }
原始数据示例
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:返回平面参数树结构的函数
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;
}
我根据@Halcyon答案写了一个 ES6 版本
const array = [
{
id: '12',
parentId: '0',
text: 'one-1'
},
{
id: '6',
parentId: '12',
text: 'one-1-6'
},
{
id: '7',
parentId: '12',
text: 'one-1-7'
},
{
id: '9',
parentId: '0',
text: 'one-2'
},
{
id: '11',
parentId: '9',
text: 'one-2-11'
}
];
// Prevent changes to the original data
const arrayCopy = array.map(item => ({ ...item }));
const listToTree = list => {
const map = {};
const roots = [];
list.forEach((v, i) => {
map[v.id] = i;
list[i].children = [];
});
list.forEach(v => (v.parentId !== '0' ? list[map[v.parentId]].children.push(v) : roots.push(v)));
return roots;
};
console.log(listToTree(arrayCopy));
该算法的原理是使用"map"来建立索引关系。通过"parentId"很容易在列表中找到"item",并在每个"item"中添加"child",因为"list"是一个引用关系,所以"roots"会与整个树建立关系。
根据@FurkanO的回答,我创建了另一个不会改变原始数据的版本(如@Dac0d3r请求的那样(。我真的很喜欢@shekhardtu的回答,但意识到它必须多次过滤数据。我认为一个解决方案可能是通过首先复制数据来使用 FurkanO 的答案。我在 jsperf 中尝试了我的版本,不幸的是(非常(黯淡的结果......看来公认的答案真的是一个好答案!不过,我的版本是可配置的和故障安全的,所以我还是与你们分享;以下是我的贡献:
function unflat(data, options = {}) {
const { id, parentId, childrenKey } = {
id: "id",
parentId: "parentId",
childrenKey: "children",
...options
};
const copiesById = data.reduce(
(copies, datum) => ((copies[datum[id]] = datum) && copies),
{}
);
return Object.values(copiesById).reduce(
(root, datum) => {
if ( datum[parentId] && copiesById[datum[parentId]] ) {
copiesById[datum[parentId]][childrenKey] = [ ...copiesById[datum[parentId]][childrenKey], datum ];
} else {
root = [ ...root, datum ];
}
return root
}, []
);
}
const data = [
{
"account": "10",
"name": "Konto 10",
"parentAccount": null
},{
"account": "1010",
"name": "Konto 1010",
"parentAccount": "10"
},{
"account": "10101",
"name": "Konto 10101",
"parentAccount": "1010"
},{
"account": "10102",
"name": "Konto 10102",
"parentAccount": "1010"
},{
"account": "10103",
"name": "Konto 10103",
"parentAccount": "1010"
},{
"account": "20",
"name": "Konto 20",
"parentAccount": null
},{
"account": "2020",
"name": "Konto 2020",
"parentAccount": "20"
},{
"account": "20201",
"name": "Konto 20201",
"parentAccount": "2020"
},{
"account": "20202",
"name": "Konto 20202",
"parentAccount": "2020"
}
];
const options = {
id: "account",
parentId: "parentAccount",
childrenKey: "children"
};
console.log(
"Hierarchical tree",
unflat(data, options)
);
使用 options 参数,可以配置要用作 id 或父 id 的属性。如果有人想要"childNodes": []
或其他东西,也可以配置子属性的名称。
OP 可以简单地使用默认选项:
input.People = unflat(input.People);
如果父 id 是假的(null
、undefined
或其他假值(或父对象不存在,我们将该对象视为根节点。
我的解决方案:
- 允许双向映射(根到叶子和叶子到根(
- 返回所有节点、根和叶
- 一次数据传递和非常快的性能
- 香草Javascript
/**
*
* @param data items array
* @param idKey item's id key (e.g., item.id)
* @param parentIdKey item's key that points to parent (e.g., item.parentId)
* @param noParentValue item's parent value when root (e.g., item.parentId === noParentValue => item is root)
* @param bidirectional should parent reference be added
*/
function flatToTree(data, idKey, parentIdKey, noParentValue = null, bidirectional = true) {
const nodes = {}, roots = {}, leaves = {};
// iterate over all data items
for (const i of data) {
// add item as a node and possibly as a leaf
if (nodes[i[idKey]]) { // already seen this item when child was found first
// add all of the item's data and found children
nodes[i[idKey]] = Object.assign(nodes[i[idKey]], i);
} else { // never seen this item
// add to the nodes map
nodes[i[idKey]] = Object.assign({ $children: []}, i);
// assume it's a leaf for now
leaves[i[idKey]] = nodes[i[idKey]];
}
// put the item as a child in parent item and possibly as a root
if (i[parentIdKey] !== noParentValue) { // item has a parent
if (nodes[i[parentIdKey]]) { // parent already exist as a node
// add as a child
(nodes[i[parentIdKey]].$children || []).push( nodes[i[idKey]] );
} else { // parent wasn't seen yet
// add a "dummy" parent to the nodes map and put the item as its child
nodes[i[parentIdKey]] = { $children: [ nodes[i[idKey]] ] };
}
if (bidirectional) {
// link to the parent
nodes[i[idKey]].$parent = nodes[i[parentIdKey]];
}
// item is definitely not a leaf
delete leaves[i[parentIdKey]];
} else { // this is a root item
roots[i[idKey]] = nodes[i[idKey]];
}
}
return {roots, nodes, leaves};
}
使用示例:
const data = [{id: 2, parentId: 0}, {id: 1, parentId: 2} /*, ... */];
const { nodes, roots, leaves } = flatToTree(data, 'id', 'parentId', 0);
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);
有人需要它作为多父母。 引用具有多个父项的 ID 2
const dataSet = [{
"ID": 1,
"Phone": "(403) 125-2552",
"City": "Coevorden",
"Name": "Grady"
},
{"ID": 2,
"Phone": "(403) 125-2552",
"City": "Coevorden",
"Name": "Grady"
},
{
"ID": 3,
"parentID": [1,2],
"Phone": "(979) 486-1932",
"City": "Chełm",
"Name": "Scarlet"
}];
const expectedDataTree = [
{
"ID":1,
"Phone":"(403) 125-2552",
"City":"Coevorden",
"Name":"Grady",
"childNodes":[{
"ID":2,
"parentID":[1,3],
"Phone":"(979) 486-1932",
"City":"Chełm",
"Name":"Scarlet",
"childNodes":[]
}]
},
{
"ID":3,
"parentID":[],
"Phone":"(403) 125-2552",
"City":"Coevorden",
"Name":"Grady",
"childNodes":[
{
"ID":2,
"parentID":[1,3],
"Phone":"(979) 486-1932",
"City":"Chełm",
"Name":"Scarlet",
"childNodes":[]
}
]
}
];
const createDataTree = dataset => {
const hashTable = Object.create(null);
dataset.forEach(aData => hashTable[aData.ID] = {...aData, childNodes: []});
const dataTree = [];
dataset.forEach(Datae => {
if (Datae.parentID && Datae.parentID.length > 0) {
Datae.parentID.forEach( aData => {
hashTable[aData].childNodes.push(hashTable[Datae.ID])
});
}
else{
dataTree.push(hashTable[Datae.ID])
}
});
return dataTree;
};
window.alert(JSON.stringify(createDataTree(dataSet)));
我使用了@FurkanO答案并制作了一个可以与任何对象类型一起使用的通用函数,我也在 TypeScript 中编写了这个函数,由于自动完成,我更喜欢它。
实现:
1. Javascript:
export const flatListToTree = (flatList, idPath, parentIdPath, childListPath, isParent) => {
const rootParents = [];
const map = {};
for (const item of flatList) {
if (!item[childListPath]) item[childListPath] = [];
map[item[idPath]] = item;
}
for (const item of flatList) {
const parentId = item[parentIdPath];
if (isParent(item)) {
rootParents.push(item);
} else {
const parentItem = map[parentId];
parentItem[childListPath].push(item);
}
}
return rootParents;
};
2. 打字稿:我假设"T"类型具有子列表的属性,如果您有不同的用例,您可以将"childListPath"更改为字符串而不是"keyof T"。
export const flatListToTree = <T>(
flatList: T[],
idPath: keyof T,
parentIdPath: keyof T,
childListPath: keyof T,
isParent: (t: T) => boolean,
) => {
const rootParents: T[] = [];
const map: any = {};
for (const item of flatList) {
if (!(item as any)[childListPath]) (item as any)[childListPath] = [];
map[item[idPath]] = item;
}
for (const item of flatList) {
const parentId = item[parentIdPath];
if (isParent(item)) {
rootParents.push(item);
} else {
const parentItem = map[parentId];
parentItem[childListPath].push(item);
}
}
return rootParents;
};
如何使用:
const nodes = [
{ id: 2, pid: undefined, children: [] },
{ id: 3, pid: 2 },
{ id: 4, pid: 2 },
{ id: 5, pid: 4 },
{ id: 6, pid: 5 },
{ id: 7, pid: undefined },
{ id: 8, pid: 7 },
];
const result = flatListToTree(nodes, "id", "pid", "children", node => node.pid === undefined);
这是我根据上述答案创建的一个简单的帮助程序函数,专为 Babel 环境量身定制:
import { isEmpty } from 'lodash'
export default function unflattenEntities(entities, parent = {id: null}, tree = []) {
let children = entities.filter( entity => entity.parent_id == parent.id)
if (!isEmpty( children )) {
if ( parent.id == null ) {
tree = children
} else {
parent['children'] = children
}
children.map( child => unflattenEntities( entities, child ) )
}
return tree
}
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();
}
这是Steven Harris的修改版本,它是普通的ES5,并返回一个以id为键的对象,而不是在顶层和子级返回节点数组。
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);
这是上述的修改版本,适用于多个根项,我将 GUID 用于我的 ID 和父 ID,因此在创建它们的 UI 中,我将根项硬编码为类似 0000000-00000-00000-树根项
VAR 树 = 未平展(记录, "树根项"(;
function unflatten(records, rootCategoryId, parent, tree){
if(!_.isArray(tree)){
tree = [];
_.each(records, function(rec){
if(rec.parentId.indexOf(rootCategoryId)>=0){ // change this line to compare a root id
//if(rec.parentId == 0 || rec.parentId == null){ // example for 0 or null
var tmp = angular.copy(rec);
tmp.children = _.filter(records, function(r){
return r.parentId == tmp.id;
});
tree.push(tmp);
//console.log(tree);
_.each(tmp.children, function(child){
return unflatten(records, rootCategoryId, child, tree);
});
}
});
}
else{
if(parent){
parent.children = _.filter(records, function(r){
return r.parentId == parent.id;
});
_.each(parent.children, function(child){
return unflatten(records, rootCategoryId, child, tree);
});
}
}
return tree;
}
从互联网复制http://jsfiddle.net/stywell/k9x2a3g6/
function list2tree(data, opt) {
opt = opt || {};
var KEY_ID = opt.key_id || 'ID';
var KEY_PARENT = opt.key_parent || 'FatherID';
var KEY_CHILD = opt.key_child || 'children';
var EMPTY_CHILDREN = opt.empty_children;
var ROOT_ID = opt.root_id || 0;
var MAP = opt.map || {};
function getNode(id) {
var node = []
for (var i = 0; i < data.length; i++) {
if (data[i][KEY_PARENT] == id) {
for (var k in MAP) {
data[i][k] = data[i][MAP[k]];
}
if (getNode(data[i][KEY_ID]) !== undefined) {
data[i][KEY_CHILD] = getNode(data[i][KEY_ID]);
} else {
if (EMPTY_CHILDREN === null) {
data[i][KEY_CHILD] = null;
} else if (JSON.stringify(EMPTY_CHILDREN) === '[]') {
data[i][KEY_CHILD] = [];
}
}
node.push(data[i]);
}
}
if (node.length == 0) {
return;
} else {
return node;
}
}
return getNode(ROOT_ID)
}
var opt = {
"key_id": "ID", //节点的ID
"key_parent": "FatherID", //节点的父级ID
"key_child": "children", //子节点的名称
"empty_children": [], //子节点为空时,填充的值 //这个参数为空时,没有子元素的元素不带key_child属性;还可以为null或者[],同理
"root_id": 0, //根节点的父级ID
"map": { //在节点内映射一些值 //对象的键是节点的新属性; 对象的值是节点的老属性,会赋值给新属性
"value": "ID",
"label": "TypeName",
}
};
npm 包数组到树 https://github.com/alferov/array-to-tree。它将节点的普通数组(带有指向父节点的指针(转换为嵌套数据结构。
解决了将从数据库检索到的数据集转换为嵌套数据结构(即导航树(的问题。
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
*/
你可以在这里或 NPM 使用来自 Github 的这个"treeify"包。
安装:
$ npm install --save-dev treeify-js
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