Add second example showing shiny.destroy capabilities (#12)

* Add sleep example of shiny.destroy v shiny

* Make a better comparison of shiny v shiny.destroy

* Fix fill in example app

* Make app truly comparable

inst/examples-shiny/02_sleep/app.R

@@ -0,0 +1,112 @@
+library(bslib)
+library(shiny)
+library(shiny.destroy)
+
+boxModuleUI <- function(id) {
+  ns <- NS(id)
+
+  bslib::card(
+    id = ns("card"),
+    h3("Box for", sub("_", " ", id)),
+    actionButton(ns("destroy"), "Remove card")
+  )
+}
+
+boxModuleServer <- function(id, create_card, destroyable = FALSE) {
+  moduleServer(id, function(input, output, session) {
+    observeEvent(create_card(), Sys.sleep(1L))
+    observeEvent(input$destroy, {
+      if (destroyable) {
+        destroyModule()
+      } else {
+        removeUI(paste0("#", session$ns("card")))
+      }
+    })
+  })
+}
+
+destroyableBoxModuleUI <- makeModuleUIDestroyable(boxModuleUI)
+destroyableBoxModuleServer <- makeModuleServerDestroyable(boxModuleServer)
+
+comparisonModuleUI <- function(id, title) {
+  ns <- NS(id)
+
+  tagList(
+    h2(title),
+    bslib::layout_columns(
+      div(
+        p("Number of boxes:", textOutput(ns("n_modules"), inline = TRUE)),
+        p("Time taken to create last box:", textOutput(ns("time_elapsed"), inline = TRUE)),
+        actionButton(ns("create"), "Create new module")
+      ),
+      div(
+        h3("Inputs"),
+        verbatimTextOutput(ns("inputs"))
+      ),
+      col_widths = c(3, 9)
+    ),
+    div(id = ns("cards"))
+  )
+}
+
+comparisonModuleServer <- function(id, destroyable = FALSE) {
+  module_server_fn <- if (destroyable) destroyableBoxModuleServer else boxModuleServer
+  module_ui_fn <- if (destroyable) destroyableBoxModuleUI else boxModuleUI
+
+  moduleServer(id, function(input, output, session) {
+    card_id <- reactiveVal(1L)
+    ns <- session$ns
+
+    observeEvent(input$create, {
+      ns_id <- paste0("card_", card_id())
+      cards_id <- ns("cards")
+      insertUI(paste0("#", cards_id), "beforeEnd", module_ui_fn(id = ns(ns_id)))
+      module_server_fn(id = ns_id, create_card = reactive(input$create), destroyable = destroyable)
+
+      card_id(card_id() + 1L)
+    })
+
+    output$n_modules <- renderText({
+      sum(grepl(ns("destroy"), names(input)))
+    })
+
+    output$inputs <- renderPrint({
+      inputs <- vapply(names(input), \(x) paste0(x, ": ", input[[x]]), character(1L))
+      cat(inputs, sep = "\n")
+    })
+
+    time_init <- reactiveVal(NULL)
+    time_end <- reactiveVal(NULL)
+
+    observeEvent(input$create, priority = 1L, time_init(Sys.time()))
+    observeEvent(input$create, priority = -1L, time_end(Sys.time()))
+
+    output$time_elapsed <- renderText(paste0(round(time_end() - time_init()), "s")) |>
+      bindEvent(time_end())
+  })
+}
+
+ui <- bslib::page_fluid(
+  title = "shiny.destroy comparison",
+  h1("shiny v shiny.destroy comparison"),
+  p(
+    "For each box module created, a second will elapse. As more boxes are created, the longer",
+    "it will take for the app to become responsive again."
+  ),
+  p(
+    "Click the new modules and see the time comparison it takes to create a new destroyable",
+    "module after some boxes have been deleted compared to using standard shiny calls"
+  ),
+  bslib::layout_columns(
+    comparisonModuleUI("shiny", "Shiny modules"),
+    comparisonModuleUI("shiny_destroy", "Destroyable modules"),
+    fillable = FALSE
+  )
+)
+
+server <- function(input, output, session) {
+  comparisonModuleServer("shiny")
+  comparisonModuleServer("shiny_destroy", destroyable = TRUE)
+}
+
+shinyApp(ui, server)