<div id="filter"></div>
<script>
  var data = [
      { name: "Jane Doe", age: 30 },
      { name: "John Doe", age: 33 }
    ];

  var dataSource = new kendo.data.DataSource({
    data: data
  });

  $("#filter").kendoFilter({
    dataSource: dataSource,
    operators: {
        string: {
            custom: {
                text: "Custom Filter",
                handler: (data) => {
                    console.log("Custom filter applied", data);
                    return true;
                }
            }
        }
    },
    fields: [
      { name: "name", type: "string", label: "Name" }
    ]
  });
</script>