NA handling in `filter_slider` and `filter_select`

[roaldarbol]

It would be great to have the option to let filter_slider know what to do with missing values (e.g. NA). I could imagine the options missing = c("top", "bottom", "hide"). There are times when a missing value could mean any value, which would be a reason one might want to include them - and top and bottom could provide the instruction about where to place them. Other times, most often, they will actually mean that the value is missing - and so I'd expect missing to be the default choice.

I noticed that you have previously mentioned that NA handling is TO DO

crosstalk/R/controls.R

Lines 301 to 307 in 46d12a6

	filter_slider <- function(id, label, sharedData, column, step = NULL,
	round = FALSE, ticks = TRUE, animate = FALSE, width = NULL, sep = ",",
	pre = NULL, post = NULL, timeFormat = NULL,
	timezone = NULL, dragRange = TRUE, min = NULL, max = NULL)
	{
	# TODO: Check that this works well with factors
	# TODO: Handle empty data frame, NA/NaN/Inf/-Inf values

...maybe this could be the way to do it?

[roaldarbol]

On second thought, the data should probably just follow the existing sorting - so maybe instead just na_include = c(TRUE, FALSE) or the standard na.rm = c(TRUE, FALSE) although it could also apply to NaN, Inf etc.

This would probably also make sense for filter_select come to think of it!