FR: UI pageSpinner

[ismirsehregal]

It would be great to have a pageSpinner function which can be used to show a pageSpinner on session start - similar to shinyjs::hidden() and shinyjs::hide().

With bigger server functions the showPageSpinner call is delayed, which could be avoided with a client side solution:

library(shiny)
library(shinycssloaders)

ui <- fluidPage()

server <- function(input, output, session) {
  Sys.sleep(3L)
  shinycssloaders::showPageSpinner()
}

shinyApp(ui, server)