How to sort TreeView nodes level wise in EJ2 JavaScript TreeView

4 Sep 20269 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 only, refer to the following code sample, which demonstrates how to sort a specific level of nodes in the TreeView.

// Hierarchical data source for TreeView control
var countries = [
    { 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' }

];
var newData;

var tree1 = new ej.navigations.TreeView({
    fields: { dataSource: countries, id: 'id', text: 'name', parentID: 'pid', 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
    var resultData = new ej.data.DataManager(this.getTreeData()).executeLocal(new ej.data.Query().where(this.fields.parentID, 'equal', null, false));
    var name = [];
    for (var i = 0; i < resultData.length; i++) {
        name.push(resultData[i][this.fields.text]);
    }
    name.sort();
    var arr = [];
    for (var j = 0; j < name.length; j++) {
        var sortedData = new ej.data.DataManager(this.getTreeData()).executeLocal(new ej.data.Query().where(this.fields.text, 'equal', name[j], false));
        var childData = new ej.data.DataManager(newData).executeLocal(new ej.data.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) {
    if (args.isInteracted && args.node.querySelector('li') === null) {
        var childData = new ej.data.DataManager(newData).executeLocal(new ej.data.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/ej2/34.2.2/ej2-base/styles/bootstrap5.3.css" rel="stylesheet">
  <link href="https://cdn.syncfusion.com/ej2/34.2.2/ej2-inputs/styles/bootstrap5.3.css" rel="stylesheet">
  <link href="https://cdn.syncfusion.com/ej2/34.2.2/ej2-navigations/styles/bootstrap5.3.css" rel="stylesheet">
  <script src="https://cdn.syncfusion.com/ej2/34.2.2/dist/ej2.min.js" type="text/javascript"></script>
</head>

<body>
  <div id="container">
    <div id="treeparent">
      <div id="tree"></div>
    </div>
  </div>

  <script>
    var ele = document.getElementById('container');
    if (ele) {
      ele.style.visibility = "visible";
    }   
  </script>
  <script src="index.js" type="text/javascript"></script>
  <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%;
}