Possible to show console messages (written with `message`) in a shiny ui?

Question

I don\'t understand R\'s message vs cat vs print vs etc. too deeply, but I\'m wondering if it\'s possible to capture messages and show them in a shiny app?

Example:

Answer 1

I know this isn't nearly as elegant, but I worked around a bit similar problem using capture.output; sadly sink doesn't allow simultaneous capture of messages and output though. You don't get them in the original order, but you can extract both streams at least (here turned to HTML):

runApp(shinyApp(
  ui = fluidPage(
    uiOutput("test")
  ),
  server = function(input,output, session) {
    output$test <- renderUI({
      HTML(
      paste(capture.output(type = "message", expr = { 
        message(capture.output(type = "output", expr = {
          cat("test cat
")
          message("test message")
          cat("test cat2
")
          message("test message2")
        }))
      }), collapse="
")
  )})
 })
)

Output:

test message
test message2
test cat
test cat2

Perhaps in the case if user wants to capture both but also separate them, this will provide a handy work-around. (Your shinyjs package seems neat, need to take a look at it!)