Answers

• kthorngren Posts: 20,425Questions: 26Answers: 4,794

  January 2021

  FixedColumns, SearchPanes and likely other extensions call the draw() API as part of their initialization. You can see this behavior in this example using the preDraw and draw events.
  http://live.datatables.net/beribipu/2/edit

  Kevin
• sbellad Posts: 5Questions: 3Answers: 0

  January 2021 edited January 2021

  Think this is a bug as I have 28 columns and 150 rows on the page that needs footer sum calculations. Since footer is called 3 times it makes it visibly slow.
  Hoped there is a defredDraw event which would use a queue to avoid multiple draws within x mills

  just for info...I am using this hack as workaround:

  var lastFooterCallback = 0;
  var delay = 200;
  $(document).ready(function() {
     dataTable = $('#example').DataTable({
          // ...
          footerCallback: function ( row, data, start, end, display ) {
              if (lastFooterCallback >= (Date.now() - delay))
                  return;
              lastFooterCallback = Date.now();
              // footer code here
  
• kthorngren Posts: 20,425Questions: 26Answers: 4,794

  January 2021 edited January 2021

  The footerCallback docs state this:

  Identical to headerCallback but for the table footer this function allows you to modify the table footer on every 'draw' event.

  So it is working as expected and will run any time the Datatable is drawn, ie, searches, paging, sorting and when certain extensions are initialized and need to draw the table. Maybe you can use a global variable flag to skip running the footerCallback during initialization and only run it after, for example:
  http://live.datatables.net/beribipu/3/edit

  EDIT: Added searchpanes to the example.

  Kevin