Events shiny:visualchange, shiny:conditional, and shiny:recalculating

R/shiny.R

@@ -471,6 +471,8 @@ ShinySession <- R6Class(
 
         obs <- observe({
 
+          self$sendCustomMessage('recalculating', list(name = name))
+
           value <- try(
             {
               tryCatch(

srcjs/init_shiny.js

@@ -253,7 +253,12 @@ function initShiny() {
       }
     });
     $('.shiny-bound-output').each(function() {
-      $(this).data('shiny-output-binding').onResize();
+      var $this = $(this), binding = $this.data('shiny-output-binding');
+      $this.trigger({
+        type: 'shiny:visualchange',
+        binding: binding
+      });
+      binding.onResize();
     });
   }
   var sendImageSizeDebouncer = new Debouncer(null, doSendImageSize, 0);

srcjs/shinyapp.js

@@ -310,6 +310,10 @@ var ShinyApp = function() {
       var show = condFunc(scope);
       var showing = el.css("display") !== "none";
       if (show !== showing) {
+        el.trigger({
+          type: 'shiny:conditional',
+          show: show
+        });
         if (show) {
           el.trigger('show');
           el.show();
@@ -503,6 +507,14 @@ var ShinyApp = function() {
     }
   });
 
+  addCustomMessageHandler('recalculating', function(message) {
+    if (message.hasOwnProperty('name')) return;
+    $('#' + message.name).trigger({
+      type: 'shiny:recalculating'
+    });
+  });
+
+
   // Progress reporting ====================================================
 
   var progressHandlers = {