library(shiny)

typingSpeedInput <- function(inputId, label, placeholder = NULL) {
  .label <- label
  htmltools::withTags(
    div(
      class = "form-group typing-speed",
      label(class = "control-label", `for` = inputId, .label),
      textarea(id = inputId, class = "form-control", placeholder = placeholder)
    )
  )
}

ui <- fluidPage(
  # textAreaInput("typing", "Type here..."),
  typingSpeedInput("typing", "Type here..."),
  verbatimTextOutput("debug")
)

server <- function(input, output, session) {
  output$debug <- renderPrint(input$typing)
}

shinyApp(ui, server)