API column().render()

CuskitLimited

My aim is to have a generic footerCallback that uses an object in the same format as a row of the data that will work for every table I'm using.

To do this I'm trying access the renderer defined against a column so that when adding values to the footer I can render values using the same function as the cells in the body of the table.

For example I want to call dt.columns(4).render(1234.5, 'display') on a column with render: $.fn.dataTable.render.number( ',', '.', 2, '£' ) and output £1,234.50.

I've managed to put together a very nasty hack to get my desired result but it involves changing the value of the first cell in the column and using that to call render.

$.fn.dataTable.Api.register( 'column().render()', function (value, type) {
    var cell = this.cell(this.nodes()[0]);
    var originalData = cell.data();
    cell.data(value);
    var output = cell.render(type);
    cell.data(originalData);
    return output;
} );

I couldn't see any way to access the columns render setting through the API so that was the only way I could get it to work.
Is there any way of doing something like this that accesses the columns renderer directly?

allan

Do you want to get the rendered data for the whole column - if so, use:

table.cells( null, columnIndex ).render( 'display' );

(i.e. select all of the cells in a column - basically a column selector!). DataTables 2 has a column().render() method committed into it already you'll be pleased to hear.

However, if you want to use a column renderer directly use:

var numberRenderer = $.fn.dataTable.render.number( ',', '.', 2, '£' );

Then for the column columns.render option assign numberRenderer to it.

In the footer calculations use numberRenderer.display( numberToRender );

Allan

CuskitLimited

Good to hear it's already in DT2 - is there a planned timescale on that update or is it too early to say yet?

Expanding on your suggestion, I could create an array and put the renderers in there against the column indexes and use that to define the table instead. Something like:

    var renderers = [
        $.fn.dataTable.render.text(),
        $.fn.dataTable.render.text(),
        $.fn.dataTable.render.number(',','.',0),
        $.fn.dataTable.render.number(',','.',2, '£'),
        $.fn.dataTable.render.number(',','.',2, '£')
    ];
    $('#myTable').dataTable({
        ...
        columns: [
            {
                'render':renderers[0],
                ...
            },      
            {
                'render':renderers[1],
                ...
            },
            ...
        ],
        ...
    });

and can then call renderers[4].display(1234.5) in the footer.