JQuery Tablesorter: emptyTo: 'bottom' not working for custom parser

Question

I'm using JQuery Tablesorter version 2.17.8 to sort a table
I've created a custom parser to sort a date, followed by a time, followed by an optional string.

The parser looks like this:

$.tablesorter.addParser({
id: "datetime",
is: function (s) {
    return /\d{2}\-\d{2}\-\d{2}\s\d{2}:\d{2}(door \w+)?/.test(s);
}, format: function (s) {
    arr = s.split(/[\s\-:]/);
    if(arr[0] == "") // table column is empty
        timestamp = null; 
    else {
        // Month is zero-indexed so subtract one from the month inside the constructor
        date = new Date(Date.UTC('20' + arr[2], arr[1] - 1, arr[0], arr[3], arr[4])); // Y M D H M
        timestamp = date.getTime();
    }
    console.log(timestamp);
    return timestamp;
}, type: "numeric"
});

Example data of the table column to be sorted:

• 30-04-14 09:55
• 30-04-14 14:11 door I1
• Empty cell

The parser works as intended but I want the empty cells to be sorted to the bottom and that doesn't seem to work.

I placed this in my PHP file:

<script type="text/javascript">
{literal}
$(document).ready(function() 
{ 
    $("#betalingen").tablesorter( { 
        headers: { 
            5 : { sorter: false } },        // disable sorting for column #5
        widgets: ["saveSort", "zebra"],     // apply alternating row coloring
        sortList: [[2,0]],                  // initial sorting order for Date column = ascending (0)
        emptyTo: 'bottom'                   // empty cells are always at the bottom
        } 
    ); 
} );
{/literal}
</script>

Note that I've tried every option here: http://mottie.github.io/tablesorter/docs/example-option-sort-empty.html
And when I remove my custom parser (and let Tablesorter figure out a parser), it sorts the empty cells to the bottom as intended but obviously the column isn't sorted correctly.

Anyone knows what is going on here?

Answer 1

You'll need to tweak you parser slightly.

• You don't really need an is function since you can set the parser to a column and not need to auto-detect it.

• As @karlingen pointed out, when the cell is empty, you're still returning timestamp which has been set to null; it gets saved as null and not an empty string.

  $.tablesorter.addParser({
      id: "datetime",
      is: function (s) {
          // no need to auto-detect
          return false;
      },
      format: function (s) {
          var date, timestamp,
              arr = s.split(/[\s\-:]/);
          if (arr[0] !== "") {
              // Month is zero-indexed so subtract one from the month inside the constructor
              date = new Date(Date.UTC('20' + arr[2], arr[1] - 1, arr[0], arr[3], arr[4])); // Y M D H M
              timestamp = date.getTime();
          }
          // is date really a date?
          return date instanceof Date && isFinite(date) ? timestamp : s;
      },
      type: "numeric"
  });