perf(treeTable): 改进 flatToTree (#1912)

* perf(treeTable): 改进 flatToTree 性能

* test: 新增 treeTable 平铺模式的测试数据

* test: 微调 treeTable 测试用例

* refactor(treeTable): 剔除多余循环，进一步优化性能

* fix: 修复一些边缘情况

---------

Co-authored-by: 贤心 <3277200+sentsim@users.noreply.github.com>

examples/json/treeTable/demo-simple.json

@@ -0,0 +1,33 @@
+{
+  "code": 0,
+  "count": 100,
+  "data": [
+    {
+      "id":1,"name":"User-1","type":1,"status":2,"score":11,"experience":123,"sex":"女","city":"北京市","description":"-","createTime":"2016-10-14 10:00:00","parentId":null
+    },
+    {
+      "id":2,"name":"User-2","type":1,"status":2,"score":22,"experience":456,"sex":"男","city":"上海市","description":"-","createTime":"2016-10-14 10:00:00","parentId":1
+    },
+    {
+      "id":3,"name":"User-3","type":1,"status":2,"score":33,"experience":777,"sex":"男","city":"广州市","description":"-","createTime":"2016-10-14 10:00:00","parentId":2
+    },
+    {
+      "id":4,"name":"User-4","type":1,"status":2,"score":44,"experience":888,"sex":"男","city":"深圳市","description":"-","createTime":"2016-10-14 10:00:00","parentId":null
+    },
+    {
+      "id":5,"name":"User-5","type":1,"status":2,"score":55,"experience":999,"sex":"男","city":"重庆市","description":"-","createTime":"2016-10-14 10:00:00","parentId":null
+    },
+    {
+      "id":6,"name":"User-6","type":1,"status":2,"score":66,"experience":1000,"sex":"男","city":"成都市","description":"-","createTime":"2016-10-14 10:00:00","parentId":5
+    },
+    {
+      "id":7,"name":"User-7","type":1,"status":2,"score":77,"experience":1001,"sex":"男","city":"苏州市","description":"-","createTime":"2016-10-14 10:00:00","parentId":5
+    },
+    {
+      "id":8,"name":"User-8","type":1,"status":2,"score":88,"experience":1002,"sex":"男","city":"杭州市","description":"-","createTime":"2016-10-14 10:00:00","parentId":null
+    },
+    {
+      "id":9,"name":"User-9","type":1,"status":2,"score":99,"experience":1003,"sex":"男","city":"武汉市","description":"-","createTime":"2016-10-14 10:00:00","parentId":null
+    }
+  ]
+}

examples/treeTable.html

@@ -44,6 +44,9 @@ layui.use(['treeTable', 'dropdown', 'layer'], function(){
       },
       view: {
         iconLeaf: ''
+      },
+      data: {
+        // isSimpleData: true
       }
     },
     cols: [[

src/modules/treeTable.js

@@ -325,31 +325,40 @@ layui.define(['table'], function (exports) {
     idKey = idKey || 'id';
     pIdKey = pIdKey || 'parentId';
     childrenKey = childrenKey || 'children';
-    // 创建一个空的 nodes 对象，用于保存所有的节点
+    // 创建一个空的 map 对象，用于保存所有的节点
-    var nodes = {};
+    var map = {};
-    // 遍历所有节点，将其加入 nodes 对象中
+    var rootNodes = [];
+
     var idTemp = '';
-    layui.each(flatArr, function (index, item) {
-      idTemp = idKey + item[idKey];
-      nodes[idTemp] = $.extend({}, item);
-      nodes[idTemp][childrenKey] = [];
-    })
-    // 遍历所有节点，将其父子关系加入 nodes 对象
     var pidTemp = '';
-    layui.each(nodes, function (index, item) {
+    layui.each(flatArr, function(index, item){
+      idTemp = idKey + item[idKey];
       pidTemp = idKey + item[pIdKey];
-      if (pidTemp && nodes[pidTemp]) {
+
-        nodes[pidTemp][childrenKey].push(item);
+      // 将节点存入 map 对象
+      if(!map[idTemp]){
+        map[idTemp] = {};
+        map[idTemp][childrenKey] = [];
       }
-    })
+
-    // 返回顶层节点
+      // 合并节点
-    return Object.keys(nodes)
+      var tempObj = {};
-      .map(function(k) {
+      tempObj[childrenKey] = map[idTemp][childrenKey];
-        return nodes[k];
+      map[idTemp] = $.extend({}, item, tempObj);
-      })
+
-      .filter(function (item) {
+      var isRootNode = (rootPid ? map[idTemp][pIdKey] === rootPid : !map[idTemp][pIdKey]);
-        return rootPid ? item[pIdKey] === rootPid : !item[pIdKey];
+      if(isRootNode){
-      })
+        rootNodes.push(map[idTemp]);
+      }else{
+        if(!map[pidTemp]){
+          map[pidTemp] = {};
+          map[pidTemp][childrenKey] = [];
+        }
+        map[pidTemp][childrenKey].push(map[idTemp]);
+      }
+    });
+
+    return rootNodes;
   }
 
   Class.prototype.flatToTree = function (tableData) {