fix #169: do not actually write select options in <option></option>, …

…but store them as JSON in the data-options attribute of <select> instead; this will significantly reduce the size of the data to be serialized

NEWS.md

@@ -69,6 +69,8 @@
 
 - Fixed a bug that triggers a DataTables warning dialog box in the browser (thanks, @zross, https://github.com/WHOequity/who-heat/issues/229 and https://github.com/rstudio/shiny/issues/561)
 
+- Factors will a huge number of levels may slow down the rendering of the table significantly (thanks, @vnijs, #169).
+
 # CHANGES IN DT VERSION 0.1
 
 - Initial CRAN release.

R/datatables.R

@@ -409,7 +409,7 @@ filterRow = function(
  if (t != 'disabled') tags$div(
  tags$select(
  multiple = 'multiple', style = 'width: 100%;',
- lapply(d, function(x) tags$option(value = x, x))
+ `data-options` = jsonlite::toJSON(as.character(d))
  ),
  style = 'width: 100%; display: none;'
  )

inst/htmlwidgets/datatables.js

@@ -224,7 +224,11 @@ HTMLWidgets.widget({
  if ($input.val() === '') filter[0].selectize.setValue([]);
  }
  });
- filter = $x.children('select').selectize({
+ var $input2 = $x.children('select');
+ filter = $input2.selectize({
+ options: $input2.data('options').map(function(v, i) {
+ return ({text: v, value: v});
+ }),
  plugins: ['remove_button'],
  hideSelected: true,
  onChange: function(value) {