andrewsali

#' An example to create asyncronously evaluated eventReactives.
library(shiny)

#' An async version of eventReactive, using the 'future' package to spawn a seperate process to evaluate the handler expression. 
#' Unlike in usual eventReactive, the handlerExpr cannot have a side-effect on the main application, as it is evaluated in a seperate
#' process.
#' @param eventExpr The expression triggering the handlerExpr. It is evaluated _synchronously_.
#' @param handlerExpr The expression being calculated in async.
#' @return Returns a reactive that can be used in other reactives that depend on the async result
eventReactiveAsync <- function(eventExpr,handlerExpr,event.env = parent.frame(),handler.env=parent.frame(),...) {

andrewsali

library(shiny)
library(shinycssloaders)
library(ggplot2)

# for spinners 2-3 match the background color of wellPanel
options(spinner.color.background="#F5F5F5")

ui <- fluidPage(
  wellPanel(
    tags$b("This example shows the loading spinner whilst the plot is loading and hides the spinner when the plot is not shown."),