Sorting treeview level wise in EJ2 TypeScript Treeview control

2 May 20238 minutes to read

You can sort the TreeView nodes based on their level. When using the sortOrder property, the whole TreeView is sorted. When you sort a particular level, you can use the following code sample. The following code sample demonstrates how to sort the parent node alone in TreeView.

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

/**
 * TreeView Sort treeview level wise
 */

    // List data source for TreeView component
   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 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'
    }
}

let newData;
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', undefined, false));
    let name = [];
    for (let i = 0; i < resultData.length; i++){
        name.push(resultData[i][this.fields.text]);
    }
    name.sort();
    let arr = [];
    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), false));
        tree1.addNodes(childData, 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/ej2/25.1.35/ej2-base/styles/material.css" rel="stylesheet" />
      <link href="https://cdn.syncfusion.com/ej2/25.1.35/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/25.1.35/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>
</body>

</html>