`boundaryScale` option of Scroller ignored?

crazyPhD

Hi everybody,

while trying to tune the values for the Scroller extension in my project, I noticed that changes to the value of boundaryScale basically show weird effects?!

Some excerpt from my DT initialization:

options = {
  "processing": true,
  "serverSide": true,
  "paging": true,
  "pageLength": 25,
  "ajax": iniData["dataUrl"],
  "order": iniData["order"],
  "columnDefs": iniData["columnDefs"],
  "dom": "lrtip",
  "searching": true,
  "createdRow": function(row, data, idx){
                        // Highlight rows for ratings
                        if (data.indexOf("critical") > -1) {
                            $(row).addClass("highlight-critical");
                        }
                        if (data.indexOf("important") > -1) {
                            $(row).addClass("highlight-important");
                        }

                        // Highlight rows for KPIs
                        data.forEach(function(item, index){
                            if (typeof item == typeof "") {
                                if (item.indexOf("KPI:") > -1 && item.indexOf("KPI: Other") < 0) {
                                    $(row).addClass("highlight-kpi");
                                }
                            }
                        });
  },
  "autoWidth": false
}
options["scrollY"] = $("#overview_tabcontent").innerHeight() - 160;
options["scroller"] = {
  "displayBuffer": 9,
  "boundaryScale": 1,
  "loadingIndicator": true,
  "serverWait": 100
};
oTable = $(iniData["tableId"]).DataTable(options);

Watching the AJAX requests made by DataTables/Scroller seem a bit weird to me; depending on the value of boundaryScale the behavior is weird in different ways. In the table I have listed the values of the start and length parameters of these requests

boundaryScale = 1

IMHO the first request after initialization is done way too early! If I have X rows in the table, I should be able to scroll to the last row present in the table before another AJAX request is made. The following AJAX requests look fine: New data is loaded when I have reached the last row.

displayBuffer = 9

Event	start	length	rows returned
Initialization	0	117	100
Scrolled down approx. to position 50	10	81	81
Scrolled down approx. to position 80	44	81	81
Scrolled down approx. to position 120	82	81	81

displayBuffer = 7

Event	start	length	rows returned
Initialization	0	91	91
Scrolled down to approx. position 25	2	63	63
Scrolled down to approx. position 60	32	63	63
Scrolled down to approx. position 90	60	63	63

boundaryScale = 1, displayBuffer = 7

Event	start	length	rows returned
Initialization	0	91	91
Scrolled down to approx. position 30	4	63	63
Scrolled down to approx. position 55	26	63	63
Scrolled down to approx. position 85	50	63	63
Scrolled down to approx. position 100	72	63	63

allan

This is in part related to the fact that the table is empty when a server-side processing table is initialised. The calculation to get the number of rows is "confused" by that (the pageLength: 25 is more or less ignored) resulting in what you see.

I agree, this is a pain point with Scroller and it is something I should address.

Allan