Check shiny inputs and modify if validation fails

Usage

shiny_check_input(
  inputId,
  check = NULL,
  on_check_fails,
  ...,
  quoted = FALSE,
  env = parent.frame(),
  logger_level = c("trace", "none", "debug", "info", "warning", "error"),
  session = shiny::getDefaultReactiveDomain()
)

Arguments

inputId: character, input ID
check: either a function that takes the input value or a character of a checkmate function; when check is a character, this function will look for check_* functions in the checkmate package
on_check_fails: value to substitute when check fails, and the input value will be the result of on_check_fails. This argument can be missing; when missing, input value will not be altered
...: passed to check function
quoted: whether on_check_fails is quoted
env: environment to evaluate on_check_fails
logger_level: log level when validation fails
session: shiny session; default is current session

Value

A shiny observe instance

Examples


if(interactive()) {

library(ravedash)
shiny::shinyApp(
  ui = shiny::basicPage(
    shiny::textInput("id1", "Enter a text"),
    shiny::textOutput("id2")
  ),
  server = function(input, output, session) {
    # input$id1 must have at least 1 character
    # the check uses `checkmate::check_character`
    shiny_check_input(
      "id1",
      check = "character",
      min.chars = 1,
      on_check_fails = "altered text"
    )

    output$id2 <- shiny::renderText({
      print(input$id1)
      sprintf("The final value is: %s", input$id1)
    })
  }
)

}