How to combine rows in Ninja tables Wordpress plugin using Javascript?

Here is officially recommended code for rowspan:

So if you need to combine some equal data in rows you will need to add this custom javasctipt into table and to use combine class for every column where you want to have combined rows

copied from here

https://gist.github.com/techjewel/f09864b2018c5d947959efd7c5e6dede

/*!
 * jQuery Rowspanizer Plugin (Modified) v0.1
 * https://github.com/marcosesperon/jquery.rowspanizer.js
 *
 * Copyright 2011, 2015 Marcos Esperón
 * Released under the MIT license
 * 
 * https://github.com/jquery-boilerplate/boilerplate/
 */

;( function( $, window, document, undefined ) {

  "use strict";

    var rowspanizer = "rowspanizer",
      defaults = {
        vertical_align: "top",
        columns: []
      };

    function f ( element, options ) {
      this.element = element;
      this.settings = $.extend( {}, defaults, options );
      this._defaults = defaults;
      this._name = rowspanizer;
      this.init();

    }

    $.extend( f.prototype, {
      init: function() {

        var _this = this;

        var $table = $(this.element);
        var arr = [];
        
        $table.find('tr td').removeClass('rowspan-remove').removeClass('rowspan-combine').removeAttr('rowspan').removeData('rowspan');

        $table.find('tr').each(function (r, tr) {
          $(this).find('td').each(function (d, td) {
            if (_this.settings.columns.length === 0 || _this.settings.columns.indexOf(d) !== -1) {
              var $td = $(td);
              var v_dato = $td.html();
              if(typeof arr[d] != 'undefined' && 'dato' in arr[d] && arr[d].dato == v_dato) {
                var rs = arr[d].elem.data('rowspan');
                if(rs == 'undefined' || isNaN(rs)) rs = 1;
                arr[d].elem.data('rowspan', parseInt(rs) + 1).addClass('rowspan-combine');
                $td.addClass('rowspan-remove').hide();
              } else {
                arr[d] = {dato: v_dato, elem: $td};
              };
            }
          });
        });

        $('.rowspan-combine').each(function (r, tr) {
          var $this = $(this);
          $this.attr('rowspan', $this.data('rowspan')).css({'vertical-align': _this.settings.vertical_align});
        });
      }
    } );

    $.fn[ rowspanizer ] = function( options ) {
      return this.each( function() {
        if ( !$.data( this, "plugin_" + rowspanizer ) ) {
          $.data( this, "plugin_" +
            rowspanizer, new f( this, options ) );
       }
      } );
    };

} )( jQuery, window, document );

$table.rowspanizer({vertical_align: 'middle'});


// Add the following lines if you have custom filters enabled
// No need to add if you don't have custom filters.
$table.on('after_ft_filtering', function() {
    $table.removeData('plugin_rowspanizer');
    $table.rowspanizer({vertical_align: 'middle'});
});

// Add the following lines if you have paginated data.
jQuery($table).on('after.ft.paging', function () {
    jQuery($table).removeData('plugin_rowspanizer');
    jQuery($table).rowspanizer({vertical_align: 'middle'});
})