Allow dateInput to have an unspecified value

[aronatkins]

It would be nice to allow a dateInput control to have an unspecified value. Right now, if you provide value=NULL, you get "today" by default.

The use case is one where I want to know if the user has made a explicit choice of a date value. Not choosing a date value could mean that a search is unbounded, for example.

[hadley]

as.Date(NA) would be a natural value to use here

[gmeurice]

I've tried to use the as.Date(NA), but still, when the user erase the date from dateInput widget, the returned value is still Sys.Date(), and not "", as I expected.

How could a user can choose to leave the fields empty (or to erase a wrong date input to leave it empty) whithout systematically returning "Sys.Date()" ?