Nested menuItems displaying content at each level

[Enuma]

Hi,

I am playing with shinydashboard menuItems, trying to achieve a nested (branching) structure.

Lets say you have 3 levels Global (highest instance) - Regional (middle instance, multiple items) - Local (lowest instance, multiple items per each region).

By clicking on Global, you'd get global statistics + a menu for Regional items will roll down, enabling you to click on Regional items. By clicking on one of the Regional items, you'd get regional statistics (for a given region) + a menu for Local items will roll down... A simple example would look like this:

library(shiny)
library(shinydashboard)

header <- dashboardHeader()

sidebar = dashboardSidebar(
  sidebarMenu(
    id = "tabs",
    menuItem("Global", tabName = "global",
                             menuItem("Regional_1", tabName = "regional_1",
                                      menuSubItem("Local_1_1", tabName = "local_1_1"),
                                      menuSubItem("Local_1_2", tabName = "local_1_2"),
                                      selected = TRUE),
                             menuItem("Regional_2", tabName = "regional_2",
                                      menuSubItem("Local_2_1", tabName = "local_2_1"),
                                      menuSubItem("Local_2_2", tabName = "local_2_2"),
                                      selected = TRUE),
             selected = TRUE
    )
  )
)

body = dashboardBody(
  tabItems(
    tabItem("global", "global"),
    tabItem("regional_1", "regional_1"),
    tabItem("regional_2", "regional_2"),
    tabItem("local_1_1", "local_1_1"),
    tabItem("local_1_2", "local_1_2"),
    tabItem("local_2_1", "local_2_1"),
    tabItem("local_2_2", "local_2_2")
  )
)

shinyApp(
  ui = dashboardPage(header, sidebar, body),
  server = function(input, output) { }
)

The problem is, that with this structure, the content is only displayed for the terminal nodes (lowest level items). SO answer offers a solution for 2 level structure by wrapping the higher level with a custom function:

convertMenuItem <- function(mi,tabName) {
 mi$children[[1]]$attribs['data-toggle']="tab"
 mi$children[[1]]$attribs['data-value'] = tabName
 if(length(mi$attribs$class)>0 && mi$attribs$class=="treeview"){
   mi$attribs$class=NULL
 }
 mi
}



header <- dashboardHeader()

sidebar = dashboardSidebar(
 sidebarMenu(
   id = "tabs",
   convertMenuItem(menuItem("Global", tabName = "global",
                            menuItem("Regional_1", tabName = "regional_1",
                                     menuSubItem("Local_1_1", tabName = "local_1_1"),
                                     menuSubItem("Local_1_2", tabName = "local_1_2")),
                            menuItem("Regional_2", tabName = "regional_2",
                                     menuSubItem("Local_2_1", tabName = "local_2_1"),
                                     menuSubItem("Local_2_2", tabName = "local_2_2"))
   ),
   "global"
   )
 )
)

body = dashboardBody(
 tabItems(
   tabItem("global", "global"),
   tabItem("regional_1", "regional_1"),
   tabItem("regional_2", "regional_2"),
   tabItem("local_1_1", "local_1_1"),
   tabItem("local_1_2", "local_1_2"),
   tabItem("local_2_1", "local_2_1"),
   tabItem("local_2_2", "local_2_2")
 )
)

shinyApp(
 ui = dashboardPage(header, sidebar, body),
 server = function(input, output) { }
)

Sadly, it is not possible to simply wrap both Global level and Regional levels with this function. I don't know exactly what is going on in the function, so it is hard for me to judge whether a simple modification of the convertMenuItem function would be enough for it to work properly on all levels, or whether more complex solution is needed.

Thanks for any help.