Don't print NULL to the console during renderPrint

R/shinywrappers.R

@@ -120,8 +120,11 @@ renderPlot <- function(expr, width='auto', height='auto', res=72, ...,
     plotFunc <- function() {
       # Actually perform the plotting
       result <- withVisible(func())
-      if (result$visible)
-        print(result$value)
+      if (result$visible) {
+        # Use capture.output to squelch printing to the actual console; we
+        # are only interested in plot output
+        capture.output(print(result$value))
+      }
 
       # Now capture some graphics device info before we close it
       usrCoords <- par('usr')