R Shinydashboard: How to reference box in conditionalPanel() condition argument

Question

I have a Shiny app where I would like to set a conditionalPanel() depending on whether the user selects a tabPanel from a tabBox. My question is how can I reference the panel the user selected. In my example the idea is that if the user selects "Panel1" there appears a conditional panel. As you will see I tried to set the condition in the conditionalPanel() call as condition = "input.tabs.tab1.box == 'p1'".

library(shiny)
library(shinydashboard)

ui <- dashboardPage(
  skin = "green",
  dashboardHeader(title = "Referencing Box"),
  dashboardSidebar(
    width = 250,
   sidebarMenu(
     id = "tabs",
     menuItem("First Tab", tabName =  "tab1",
              menuSubItem("Box", tabName = "box"))
   )
  ),
  dashboardBody(
    tabItem(
      tabName = "box",
      tabBox(
        id = "tb",
        title = "Two Panels",
        tabPanel(
          id = "p1",
          title = "Panel1"
        ),
        tabPanel(
          id = "p2",
          title = "Panel2"
        )
      ),
      conditionalPanel(
        condition = "input.tabs.tab1.box == 'p1'",
        box(
          id = "p3",
          title = "Conditional Panel"
        )
      )
    )
  )
)

server <- function(input, output) { }

shinyApp(ui, server)

I've seen some examples around where people referenced the upmost layer, so a menuItem with conditions like condition = "input.tabs == 'anova'", but in this case the referenced item is within a tabItem and further within a tabBox call.

Answer 1

In your case what you want to reference is what is the active tab of the "tabBox" with the id "tb".

So your condition for the conditional panel should be:

condition = "input.tb == 'p1'"

reference the tabbox that you want to know the active tab of.

Also in order to know which tabPanel is currently active you will also need to add a value parameter to the tabPanel, since id is sadly not enough.

Resulting in this code for the tabPanel

 tabPanel(
      value = "p1",
      id = "p1",
      title = "Panel1"
    ),

All together here is a working solution:

library(shiny)
library(shinydashboard)

ui <- dashboardPage(
    skin = "green",
    dashboardHeader(title = "Referencing Box"),
    dashboardSidebar(
        width = 250,
        sidebarMenu(
            id = "tabs",
            menuItem("First Tab", tabName =  "tab1",
                menuSubItem("Box", tabName = "box"))
        )
    ),
    dashboardBody(
        tabItem(
            tabName = "box",
            tabBox(
                id = "tb",
                title = "Two Panels",
                tabPanel(
                    value = "p1",
                    id = "p1",
                    title = "Panel1"
                ),
                tabPanel(
                    id = "p2",
                    title = "Panel2"
                )
            ),
            conditionalPanel(
                condition = "input.tb == 'p1'",
                box(
                    id = "p3",
                    title = "Conditional Panel"
                )
            )
        )
    )
)

server <- function(input, output) { }
shinyApp(ui, server)