Sorting treeview level wise in EJ2 JavaScript 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.

/**
 * Accordion tree sample
 */

// Hierarchical data source for TreeView component
 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 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'
    }
}

var newData;
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', undefined, 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)
    }
}
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