Show notification on shiny app startup

Question

In order to add a disclaimer to my app, I want to display a message at the launch of the app with showNotification() .

The user should not have to press a button (as per below) for the message to appear.

shinyApp(
ui = fluidPage(actionButton("show", "Show")),   
server = function(input, output) {
    observeEvent(input$show, {
      showNotification("This is a notification.")
    })   
})

Answer 1

Change to observe

   observe({
      showNotification("This is a notification.")
    })