Sorting TreeView level wise in EJ2 TypeScript TreeView control

28 Jan 20259 minutes to read

You can sort the TreeView nodes based on their level. When using the sortOrder property, the entire TreeView is sorted. If you want to sort a particular level, refer to the following code sample, which demonstrates how to sort only the parent node in the TreeView.

import { enableRipple } from '@syncfusion/ej2-base';
import { TreeView, NodeExpandEventArgs } from '@syncfusion/ej2-navigations';
import { DataManager, Query } from '@syncfusion/ej2-data';
enableRipple(true);

/**
 * TreeView Sort TreeView level wise
 */

// List data source for TreeView control
let countries: { [key: string]: Object }[] = [
    { id: 1, name: 'India', hasChild: true },
    { id: 2, pid: 1, name: 'Assam' },
    { id: 3, pid: 1, name: 'Bihar' },
    { id: 4, pid: 1, name: 'Tamil Nadu' },
    { id: 6, pid: 1, name: 'Punjab' },
    { id: 7, name: 'Brazil', hasChild: true },
    { id: 8, pid: 7, name: 'Paraná' },
    { id: 9, pid: 7, name: 'Ceará' },
    { id: 10, pid: 7, name: 'Acre' },
    { id: 11, name: 'France', hasChild: true },
    { id: 12, pid: 11, name: 'Pays de la Loire' },
    { id: 13, pid: 11, name: 'Aquitaine' },
    { id: 14, pid: 11, name: 'Brittany' },
    { id: 15, pid: 11, name: 'Lorraine' },
    { id: 16, name: 'Australia', hasChild: true },
    { id: 17, pid: 16, name: 'New South Wales' },
    { id: 18, pid: 16, name: 'Victoria' },
    { id: 19, pid: 16, name: 'South Australia' },
    { id: 20, pid: 16, name: 'Western Australia' },
    { id: 21, name: 'China', hasChild: true },
    { id: 22, pid: 21, name: 'Guangzhou' },
    { id: 23, pid: 21, name: 'Shanghai' },
    { id: 24, pid: 21, name: 'Beijing' },
    { id: 25, pid: 21, name: 'Shantou' }
];
let newData;

let tree1: TreeView = new TreeView({
    fields: { dataSource: countries, id: 'id', parentID: 'pid', text: 'name', hasChildren: 'hasChild' },
    created: onCreate,
    nodeExpanding: onNodeExpand
});
tree1.appendTo('#tree');

function changeDataSource(data) {
    tree1.fields = {
        dataSource: data, id: 'id', text: 'name', parentID: 'pid', hasChildren: 'hasChild'
    }
}

function onCreate() {
    newData = this.fields.dataSource;
    // Selects the first level nodes alone
    let resultData = new DataManager(this.getTreeData()).executeLocal(new Query().where(this.fields.parentID, 'equal', null, false));
    let name: any = [];
    for (let i = 0; i < resultData.length; i++) {
        name.push(resultData[i][this.fields.text]);
    }
    name.sort();
    let arr: any = [];
    for (let j = 0; j < name.length; j++) {
        let sortedData = new DataManager(this.getTreeData()).executeLocal(new Query().where(this.fields.text, 'equal', name[j], false));
        let childData = new DataManager(newData).executeLocal(new Query().where(this.fields.parentID, 'equal', parseInt(sortedData[0][this.fields.id]), false));
        arr.push(sortedData[0]);
    }
    // Renders treeview with sorted Nodes
    changeDataSource(arr);
    tree1.dataBind();
}
function onNodeExpand(args: NodeExpandEventArgs) {
    if (args.isInteracted && args.node.querySelector('li') === null) {
        let childData = new DataManager(newData).executeLocal(new Query().where(this.fields.parentID, 'equal', parseInt(args.nodeData.id as string), false));
        tree1.addNodes((childData as { [key: string]: Object; }[]), args.node, null)
    }
}
<!DOCTYPE html>
<html lang="en">

<head>
    <title>Essential JS 2 for TreeView </title>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta name="description" content="Essential JS 2 for TreeView UI Control" />
    <meta name="author" content="Syncfusion" />
    <link href="index.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/29.1.33/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/29.1.33/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/29.1.33/ej2-navigations/styles/material.css" rel="stylesheet" />
    <script src="https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <script src="systemjs.config.js"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>

<body>
    <div id='loader'>Loading....</div>
    <div id='container'>
        <div id='treeparent'>
            <div id="tree"></div>
        </div>
    </div>
    <style>
        #treeparent {
            display: block;
            max-width: 350px;
            max-height: 350px;
            margin: auto;
            overflow: auto;
            border: 1px solid #dddddd;
            border-radius: 3px;
        }
    </style>
</body>

</html>
#container {
  visibility: hidden;
}

#loader {
  color: #008cff;
  height: 40px;
  width: 30%;
  position: absolute;
  font-family: 'Helvetica Neue', 'calibiri';
  font-size: 14px;
  top: 45%;
  left: 45%;
}