Set relative link / anchor in R Shiny

I would like to create a drillable graphic that links to other places in my Shiny App.

library(tidyverse)
library(shiny)
library(shinydashboard)

ui <- dashboardPage(
dashboardHeader(title="My Fitness Dashboard",titleWidth =400),
####sidebar#####
dashboardSidebar(width = 240,
                 sidebarMenu(startExpanded = TRUE,
                             br(),
                             br(),
                             br(),
                             menuItem(text = 'Overview', 
                                      tabName = "fitDash"),
                             menuItem(text = 'Floors', 
                                      tabName = "floors")
                 )), #close dashboardSidebar
dashboardBody(
    tabItems(
        tabItem(tabName = 'fitDash',
                uiOutput("dashboard"), 
        ), #close tabItem

        tabItem(tabName = 'floorsUp',
                fluidRow(
                    column(width = 10,
                           box(width = 12, 
                               textOutput('floorsClimbed') #plot comments
                           ) #close box
                    )  #close column
                ) #close fluidRow
        ) #close tabItem
    ) #close tabItems
) #close dashboardBody
) #close dashboardPage


###### Server logic required to draw plots####
server <- function(input, output, session) {

output$dashboard <- renderUI({

    tags$map(name="fitMap",
             tags$area(shape ="rect", coords="130,250,240,150", alt="floors", href="https://www.w3schools.com"), 
             #tags$area(shape ="rect", coords="130,250,240,150", alt="floors", href="/floorsClimbed"), 
             tags$img(src = 'fitbit1.jpg', alt = 'System Indicators', usemap = '#fitMap') 
            ) #close tags$map
})

output$floorsClimbed <- renderText({ 
    "I walked up 12 floors today!"
})

} #close server function

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

The following line works perfectly to link to an external site:

tags$area(shape ="rect", coords="130,250,240,150", alt="floors", href="https://www.w3schools.com")

However, I would actually like to internally link to the "floorsUp" tab with something like:

tags$area(shape ="rect", coords="130,250,240,150", alt="floors", href="/floorsUp")

You could add an onclick listener to your element. Unfortunately, i can´t reproduce your example, but i modified an example app from the shiny docu.

You can send a message from javascript to shiny and trigger the javascript code by the onclick listener.

shiny::tags$a("Switch to Widgets", onclick="Shiny.onInputChange('tab', 'widgets');")

The parameters of onInputChange are the id and value. On the server side you can access the values by input$id. In our case it is input$tab. The resulting value would be widgets.

Then we can use updateTabItems to update the tabItem:

 observeEvent(input$tab, {
    updateTabItems(session, "tabs", input$tab)
  })

Additional details:

Note that the input only fires on the server side if the value changes. Therefore, we might want to add a stochastic component to the value we send.

"var message = {id: \"tab\", data: \"widgets\", nonce: Math.random()};
 Shiny.onInputChange('tab', message)")

You can find more infos here: https://shiny.rstudio.com/articles/js-send-message.html.

Reproducible example:

library(shiny)
ui <- dashboardPage(
  dashboardHeader(title = "Simple tabs"),
  dashboardSidebar(
    sidebarMenu(
      id = "tabs",
      menuItem("Dashboard", tabName = "dashboard", icon = icon("dashboard")),
      menuItem("Widgets", tabName = "widgets", icon = icon("th"))
    )
  ),
  dashboardBody(
    tabItems(
      tabItem(tabName = "dashboard",
              h5("Click the upper left hand corner of the picture to switch tabs"),
              tags$map(name="fitMap",
                       tags$area(shape ="rect", coords="10,10,200,300", alt="floors", 
                       onclick="var message = {id: \"tab\", data: \"widgets\", 
                           nonce: Math.random()}; Shiny.onInputChange('tab', message)"), 
                       tags$img(src = 'https://i.sstatic.net/U1SsV.jpg', 
                                alt = 'System Indicators', usemap = '#fitMap') 
              )   
      ),
      tabItem(tabName = "widgets",
              h2("Widgets tab content")
      )
    )
  )
)

server <- function(input, output, session) {
  observeEvent(input$tab, {
    updateTabItems(session, "tabs", input$tab$data)
  })
}

shinyApp(ui, server)