Merge pull request rstudio#279 from rstudio/joe/async

Support for Shiny async

DESCRIPTION

@@ -1,6 +1,6 @@
 Package: shinydashboard
 Title: Create Dashboards with 'Shiny'
-Version: 0.7.0
+Version: 0.7.0.9000
 Authors@R: c(
     person("Winston", "Chang", role = c("aut", "cre"), email = "winston@rstudio.com"),
     person("Barbara", "Borges Ribeiro", role = "aut", email = "barbara@rstudio.com"),
@@ -17,6 +17,7 @@ License: GPL (>= 2) | file LICENSE
 Imports:
     utils,
     shiny (>= 1.0.0),
-    htmltools (>= 0.2.6)
+    htmltools (>= 0.2.6),
+    promises
 BugReports: https://github.com/rstudio/shinydashboard
 RoxygenNote: 6.0.1.9000

NAMESPACE

@@ -30,3 +30,4 @@ export(updateTabItems)
 export(valueBox)
 export(valueBoxOutput)
 import(htmltools)
+import(promises)

NEWS.md

@@ -1,3 +1,14 @@
+shinydashboard 0.7.0.9000
+=========================
+
+## Full changelog
+
+### New features
+
+* Shiny async support: render functions can now handle promises. Instead of returning a `valueBox` to `renderValueBox`, return a promise that resolves to a `valueBox` (for example).
+
+### Bug fixes
+
 shinydashboard 0.7.0
 ====================
 

R/valueBoxOutput.R

@@ -61,6 +61,7 @@ infoBoxOutput <- valueBoxOutput
 #'
 #' shinyApp(ui, server)
 #' }
+#' @import promises
 #' @export
 renderValueBox <- function(expr, env = parent.frame(), quoted = FALSE) {
   # Convert the expression to a function
@@ -70,10 +71,16 @@ renderValueBox <- function(expr, env = parent.frame(), quoted = FALSE) {
   # send it to renderUI.
   shiny::renderUI({
     vbox <- vbox_fun()
-    tagAssert(vbox, type = "div")
+    if (is.promising(vbox)) {
+      vbox %...T>%
+        tagAssert(type = "div") %...>%
+        { .$children[[1]] }
+    } else {
+      tagAssert(vbox, type = "div")
 
-    # Strip off outer div, since it's already present in output
-    vbox$children[[1]]
+      # Strip off outer div, since it's already present in output
+      vbox$children[[1]]
+    }
   })
 }