how to make checkbox checked by default on treeview all nodes with devexpress

self.initTreeView = function (divName, dataSource, parentItemName, keyName, displayName) {`
    $("#" + divName).dxTreeView({
        dataSource: dataSource.reverse(),
        dataStructure: 'plain',
        parentIdExpr: parentItemName,
        keyExpr: keyName,
        displayExpr: displayName,
        showCheckBoxes: true,

//i want to show all checkboxes checked by default when page load selectNodesRecursive: true, scrollDirection: 'both', selected: true, onItemSelected: function () { $("#" + divName).val(getSelectedNodes(this._plainItems)); } });

    $treeview = $("#" + divName).dxTreeView('instance');
    return $treeview;
};