Shiny: how to create a confirm dialog box

Question

I would like to ask if it is possible to have a confirm dialog box, consisting of two buttons, in shiny. Say, if I click a Delete button, then the dialog box pop up. User pi

Answer 1

Neither ShinyBS nor Javascript is necessary. The trick is to use a modalDialog and set the footer to be a tagList of several tags, usually, an actionButton for the delete and a modalButton to cancel. Below is a MWE

app.R

library(shiny)

ui = fluidPage(
   mainPanel(
       actionButton("createfile", "Create"),
       actionButton("deletefile", "Delete")
   )
)

# Define server logic required to draw a histogram
server = function(session, input, output) {

   observeEvent(input$createfile, {
       showModal(modalDialog(
           tagList(
               textInput("newfilename", label = "Filename", placeholder = "my_file.txt")
           ), 
           title="Create a file",
           footer = tagList(actionButton("confirmCreate", "Create"),
                            modalButton("Cancel")
           )
       ))
   })


   observeEvent(input$deletefile, {
       showModal(modalDialog(
           tagList(
               selectInput("deletefilename", label = "Delete a file", choices = list.files(pattern="*.txt"))
           ), 
           title="Delete a file",
           footer = tagList(actionButton("confirmDelete", "Delete"),
                            modalButton("Cancel")
           )
       ))
   })

   observeEvent(input$confirmCreate, {
       req(input$newfilename)
       file.create(input$newfilename)
       removeModal()
   })

   observeEvent(input$confirmDelete, {
       req(input$deletefilename)
       file.remove(input$deletefilename)
       removeModal()
   })
}

# Run the application 
shinyApp(ui = ui, server = server)

Note, if you use shiny modules, you have to use session$ns("inputID") rather than ns("inputID"). See Tobias' answer here.