Updating counters Code

ServerFunction <- function(input, output, session) {
  
  observeEvent(input$add, {
    # remove old badge
    removeUI(selector = ".badge-danger.navbar-badge")
    
    # remove old text counter
    removeUI(selector = ".dropdown-item.dropdown-header")
    
  }, priority = 1)
  
  
  
  observeEvent(input$add, {
    
    # insert new badge
    insertUI(
      selector = "[data-toggle=\"dropdown\"]",
      where = "beforeEnd",
      ui = tags$span(
        class = "badge badge-danger navbar-badge",
        input$add
      )
    )
    
    # insert new text counter
    insertUI(
      selector = ".dropdown-menu",
      where = "afterBegin",
      ui = tags$span(
        class = "dropdown-item dropdown-header",
        sprintf("%s Items", input$add)
      )
    )
    
    # Insert message item
    insertUI(
      selector = ".dropdown-menu > .dropdown-divider",
      where = "afterEnd",
      ui = messageItem(
        message = paste("message", input$add),
        image = dashboardUserImage,
        from = "Divad Nojnarg",
        time = "today",
        color = "success"
      )
    )
  })
  
}