Shiny: prototype support for controlling Shiny target of 'sticky' progression updates [#109]

Author: HenrikBengtsson

NEWS

@@ -19,6 +19,11 @@ SIGNIFICANT CHANGES:
 
 NEW FEATURES:
 
+ * withProgressShiny() gained argument 'map', which can be used to control
+   whether the progression message should update the Shiny 'message' or the
+   Shiny 'detail' component in the Shiny progress panel, e.g.
+   map = c(message = "message") or map = c(message = "detail").
+   
  * Now supporting zero-length progressors, e.g. p <- progressor(along = x)
    where length(x) == 0.
 

R/handler_shiny.R

@@ -34,20 +34,36 @@ handler_shiny <- function(intrusiveness = getOption("progressr.intrusiveness.gui
   )
 
   ## Default: The progression message updates Shiny 'message'
-  map_args <- function(state) list(message = state$message)
+  map_args <- function(state, progression) {
+    message <- state$message
+    if (is.null(message)) return(list())
+    if (inherits(progression, "sticky")) {
+      list(detail = message)
+    } else {
+      list(message = message)
+    }
+  }
 
   ## Should progress message update another Shiny field?
   if ("message" %in% names(map)) {
     if (map["message"] == "detail") {
-     map_args <- function(state) list(detail = state$message)
+     map_args <- function(state, progression) {
+       message <- state$message
+       if (is.null(message)) return(list())
+       if (inherits(progression, "sticky")) {
+         list(message = message)
+       } else {
+         list(detail = message)
+       }
+     }
     }
   }
 
   reporter <- local({
     list(
       update = function(config, state, progression, ...) {
         amount <- if (config$max_steps == 0) 1 else progression$amount / config$max_steps
-        args <- c(list(amount = amount), map_args(state))
+        args <- c(list(amount = amount), map_args(state, progression))
         do.call(shiny::incProgress, args = args)
       }
     )