sorting - Implementing a custom sSortType and sort function for jQuery dataTables

Question

I'm having a hard time following the instructions on the documentation page. I have a table displaying the average time durations in one column, in the HH:MM format, e.g 10:45 means ten hours and forty-five minutes. I would like to be able to sort my entire table by the values in this column.

Here is my initialization code :

    var aoTable = $("#TableStatistic").dataTable({
    "bDestroy": true,
    "sDom": "<'row-fluid dt-header'<'span6'f><'span6'T>>t<'row-fluid dt-footer'<'span6'i><'span6'p>>",
    "oTableTools": {
        "aButtons": ["xls", "pdf", "print"],
        "sSwfPath": "../Content/media/swf/copy_csv_xls_pdf.swf"
    },
    "aaData": statisticsModel.byCategoriesList(),
    "aaSorting": [[0, "desc"]],
    "bPaginate": false,
    "aoColumns": [
        { "mDataProp": "CategoryName", "sTitle": "Reports.CategoryName" },
        { "mDataProp": "AverageTime", "sTitle": "Reports.AverageTime", "sSortDataType": "duration-desc"},
        { "mDataProp": "NumberOfProblemsSolved", "sTitle": "Reports.NumberOfProblemsSolved" }
    ],
    "oLanguage": MeridianTranslation.DataTable

});

Here is what I ASSUME to be the proper way to add a new sort function and a new sSortType into my table:

jQuery.extend(jQuery.fn.dataTableExt.oSort['duration-desc'] = function (x, y) {
    var xHours = parseInt(x.slice(0, x.indexOf(':')));
    var xMinutes = parseInt(x.slice(x.indexOf(':') + 1, x.length)) + xHours * 60;
    var yHours = parseInt(y.slice(0, y.indexOf(':')));
    var yMinutes = parseInt(y.slice(y.indexOf(':') + 1, y.length)) + yHours * 60;
    return ((xMinutes < yMinutes) ? -1 : ((xMinutes > yMinutes) ? 1 : 0));
});

jQuery.extend(jQuery.fn.dataTableExt.oSort['duration-asc'] = function (x, y) {
    var xHours = parseInt(x.slice(0, x.indexOf(':')));
    var xMinutes = parseInt(x.slice(x.indexOf(':')+1, x.length)) + xHours * 60;
    var yHours = parseInt(y.slice(0, y.indexOf(':')));
    var yMinutes = parseInt(y.slice(y.indexOf(':')+1, y.length)) + yHours * 60;
    return ((xMinutes < yMinutes) ? 1 : ((xMinutes > yMinutes) ? -1 : 0));
});

I suppose there is a much better way for extracting the number of minutes than the way I do it, but let's suppose my algorithm is valid. What must I do to initialize my dataTable properly and integrate this sort function and data type into it? The table itself renders properly, but when I try to sort the column in question, it sort itself lexicographically, as if it were a string. Any ideas?

Answer 1

You should provide both a <type>-asc method and a <type>-desc method.

The sort is then based on the sType property of the column:

jQuery.fn.dataTableExt.oSort["duration-desc"] = function (x, y) {
    ...
};

jQuery.fn.dataTableExt.oSort["duration-asc"] = function (x, y) {
    ...
}

var oTable = $("#products").dataTable({
    "aaData": [
        [1, "Dinner", "0:40"],
        [2, "Study", "11:25"],
        [3, "Sleep", "7:30"]
    ],
    "aoColumns": [{
        ...
    }, {
        ...
    }, {
        ...
        "bSortable": true,
        "sType": "duration"
    }]

});

Here is a simple jsFiddle example.