`boundaryScale` option of Scroller ignored?

`boundaryScale` option of Scroller ignored?

crazyPhDcrazyPhD Posts: 2Questions: 2Answers: 0

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

Answers

  • allanallan Posts: 50,248Questions: 1Answers: 7,465 Site admin

    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

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