This function takes an input value and uses heuristics to guess whether it
represents an "empty" input vs. one that the user has provided. This will
vary by input type; for example, a shiny::textInput() is "" when empty,
while a shiny::numericInput() is NA.
input_provided returns TRUE for all values except:
NULL
""
An empty atomic vector or list
An atomic vector that contains only missing (NA) values
A character vector that contains only missing and/or "" values
An object of class "try-error"
A value that represents an unclicked shiny::actionButton()
input_provided(val)Values to test for availability in a Shiny context.
A logical vector of length 1.
This function is based on shiny::isTruthy() but tweaked here in
shinyvalidate to change the treatment of FALSE values: isTruthy(FALSE)
returns FALSE, but input_provided(FALSE) returns TRUE. This difference
is motivated by shiny::checkboxInput(), where isTruthy() answers the
question of "is the input present and checked" while input_provided is
just "is the input present".