shiny-password.R

library("shiny")

x <- runApp(shinyApp(
  fluidPage(
    "Password:", 
    tags$input(id = "password", type = "password"),
    actionButton("done", "Done")
  ),
  function(input, output) {
    observe({
      input$done
      if (input$done > 0)
        stopApp(isolate(input$password))
    })
  }
))
x