有同样的问题，但我不能确定数据是否已排序。我不能使用第三方库，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

平面阵列到树

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>

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();
}

一个更简单的从列表到树的函数

NPM安装列表到树精简版

listToTree(列表)

来源:

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

经过多次尝试，我得出了这个结论:

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));

你可以用两行代码来解决这个问题:

_(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(查看浏览器控制台以获得创建的树)

要求:

1-安装lodash 4(一个Javascript库，用于操作对象和集合，使用性能方法=>，就像c#中的Linq)

2-如下所示的flatArray:

    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:[]
    }];

谢谢Bakhshabadi先生

祝你好运