fields.previewFormat String

The format of the value displayed in the preview.

Example - set the editorTemplate

<div id="filter"></div>
<br /><br />
<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,
    expressionPreview: true,
    fields: [
      {
        name: "age",
        type:"number",
        previewFormat:'n2'
      },
      { name: "name", type:"string" }
    ]
  });
</script>