Sorting by empty cells "emptyTo" Tablesorter doesn't work

Question

I have a table with some data with dates and i want it to sort by the cells that are empty. By default tablesorter places them at the bottom and i need them at the top. I read other posts related and none of them seems to work for me and i'm trying to figure out why.

I'm using Tablesorter 2.29.5

 /*! TableSorter (FORK) v2.29.5 *//*
  * Client-side table sorting with ease!
  * @requires jQuery v1.2.6+

And i'm setting the libraries properly (everything else works fine)

This is my tablesorter config in Jquery:

 $('#tablesorter')
            .tablesorter({
                theme : 'blue',
                widgets: ['filter', 'reflow','resizable'],
                sortList: [[0,0]],
                emptyTo: 'top',
                widgetOptions: {
                    resizable: true, 
                    resizable_widths : [ '12%', '12%', '10%', '10%', '10%', '10%', '17%', '9%', '9%','0%']   
                }

            }).tablesorterPager({
                container: $(".paginatorTableSorter"),
                output: '{{ "table.showing"|trans }} {startRow} {{ "table.to"|trans }} {endRow} ({filteredRows})'
            });
        $(".tablesorter").data('tablesorter').widgets = ['zebra', 'columns'];
        $(".tablesorter").trigger('applyWidgets');
        $('#tablesorter')
                .trigger('sortReset')
                .trigger('filterReset')
                .trigger('resizableReset')
                .trigger('pageAndSize', [1, 10]);

I also tried to sort by the column but since they're dates empty cells are ignored, so i'm setting emptyTo: 'top' following the jQuery tablesorter documentation https://mottie.github.io/tablesorter/docs/#emptyto

This is my (adapted) html(and Twig):

<thead>
  <tr class="warning">
    <th class="text-center">{{ 'table.title.time.check-in' |trans }}</th>
    <th class="text-center">{{ 'table.title.time.check-out' |trans }}</th>                        
  </tr>
</thead>
<tbody>
  <tr>
    <td class="text-center">{{ line.FECHA_E }}</td>
    <td class="text-center">{{ line.FECHA_S }}</td>
  </tr>
</tbody>

Is there anything i'm missing?

Answer 1

So, yes. As Mottie said i double checked the real value of the input and found the problem.

<tbody>
 <tr>
  <td class="text-center">{{ line.FECHA_E }}</td>
  <td class="text-center">{% if line.FECHA_S is null %}{% else %}{{ line.FECHA_S }}{% endif %}</td>
 </tr>
</tbody>

After posting the question i realized that i left the .trigger('sortReset') on the config but that was commented on my code.

In case anybody copies my tablesorter config just remove that part so it won't reset the default sorting values.

Once again thanks Mottie!