Sleep Shiny WebApp to let it refresh... Any alternative?

Question

I have a WebApp that have some renderUI({})... and some of them depend on the input of another.

This makes that, briefly, a red error in the webpage appear when I select some options. Because the if() clause of some renderUI({}) depend on the input of a selectizer. The error says something like "The length of the argument is 0" (As the if() depends on a TRUE/FALSE, but in that exact moment it is not TRUE nor FALSE). After a second or so, it works good.

This could be done via a Sys.sleep() after the first if() but I don't know if it's the best option.

Thank you.

Edit - Reproducible code:

ui.R

radioButtons(
    inputId="select",
    label="Some selectizer",
    choices=list(
      "Yes",
      "No"
    ),
    selected="No",
    inline=TRUE
),

uiOutput("select1"),
uiOutput("option2")

server.R

output$select1 <- renderUI({
if (input$select == "No")
  return()

else radioButtons(
  inputId="select1",
  label="Some additional selector",
  choices=list(
    "Yes",
    "No"
  ),
  selected="No",
  inline=TRUE)
})

output$option2 <- renderUI({
  if (input$select == "Yes"){
    if (input$select1 == "Yes"){
      textInput("option2", "Some textInput: "), 
    }
    else return()
  }
})

Answer 1

some reproducible code would allow me to give you some example code, but in the absence of that...

wrap what you currently have in another if(), checking for length = 0 (or just && it, with the NULL check first), and display your favorite placeholder message.