Shiny in R: How can I fade-out my plotOutput from renderPlot if certain conditions are not met?

Question

the question is straight forward. First, I tried an if-else condition within the render plot. Something like

if (input$Next > 0) {
   plot(...)
}
else {
          


        

Answer 1

Use a conditional panel like so:

library(shiny)
ui =fluidPage(
  sidebarPanel(
    conditionalPanel(condition="input.Next>0",
    plotOutput("test")),
    actionButton("Next", "Next")
  ))

server=shinyServer(function(input, output, session) {

    output$test <- renderPlot({

        req(input$Next > 0)

      pt <- plot(input$Next,2)
      print(pt)
    })

})

shinyApp(ui=ui,server=server)