calculate td tag width of table fixed layout in datatables

var table = $('#example').DataTable({
    // columns and columnDefs
});

table.columns().eq(0).each( function ( colIdx ) {
    var colWidth = table.column( colIdx ).width();
    colIdx = colIdx + 1;
    $( '#example td:nth-child('+colIdx+')' ).css( 'width', colWidth );
});