Selectize input with the initial choice after the click of a button

Question

I have a number of selectize inputs (some single choice and some multiple choice). Here is a snippet of my code:

# ui.R

library(shiny)

shinyUI(fluidPage(
    selectizeInput(
        "countries",
        "",
        choices = c("Greece", "Italy", "France", "Belgium", "Latvia"),
        multiple = FALSE
    ),
    selectizeInput(
        "resources",
        "",
        choices = c("gold", "silver", "gas", "oil", "wheat"),
        multiple = TRUE
    ),
    actionButton(
        "reset",
        "Reset"
    ) 
))

From what I understand, the default choice for the single-choice menu should be "", while for the multiple-choice menu it should be NULL.

I would like that when I click a reset button the choices of the selectize inputs go back to the initial ones, that is when I start the app. Is there any way to do this? Below is my try but it doesn't work for the multiple choice menu, and in any case I hope there is a better and more efficient option.

# server.R

library(shiny)

shinyServer(function(input, output, session) {
  observeEvent(input$reset, {
    updateSelectizeInput(session, "countries", selected = "")
    updateSelectizeInput(session, "resources", selected = NULL)
  })
})

Anyone know a practical solution?

Answer 1

You didn't define your label and your selected default. It's a good idea to do that. In the Docs it states selectize will use "" as a default if you put it in the choices instead of defining it in selected.

library(shiny)

ui <- fluidPage(
  selectizeInput(
    "countries",
    label = "Countries",
    choices = c("", "Greece", "Italy", "France", "Belgium", "Latvia"),
    multiple = FALSE
  ),
  selectizeInput(
    "resources",
    label = "Resources",
    choices = c("","gold", "silver", "gas", "oil", "wheat"),
    multiple = TRUE
  ),
  actionButton(
    inputId = "reset",
    label = "Reset"
  ) 
)



server <- function(input, output, session) {
  
  observeEvent(input$reset, {
    purrr::map(c("countries", "resources"),~ updateSelectizeInput(inputId = .x, selected = ""))
  })
  
}

shinyApp(ui, server)