helpers.R

#####===== SHOW BUSY INDICATOR FOR ACTION/DOWNLOAD BUTTONS =====#####

###= Style for "loading" and "done" elements
withBusyIndicatorCSS <- "
  .btn-loading-container {
  margin-left: 10px;
  font-size: 1.2em;
  }
  .btn-done-indicator {
  color: green;
  }
"
# .btn-err {
#   margin-top: 10px;
#   color: red;
# }

###= "Busy Indicator" button in UI
withBusyIndicatorUI <- function(button) {
  id <- button[['attribs']][['id']]
  div(
    shinyjs::useShinyjs(),
    singleton(tags$head(
      tags$style(withBusyIndicatorCSS)
    )),
    `data-for-btn` = id,
    button,
    span(
      class = "btn-loading-container",
      shinyjs::hidden(
        icon("spinner", class = "btn-loading-indicator fa-spin"),
        icon("check", class = "btn-done-indicator")
      )
    )
    # ,shinyjs::hidden(
    #   div(class = "btn-err",
    #       div(icon("exclamation-circle"),
    #           tags$b("Error: "),
    #           span(class = "btn-err-msg")
    #       )
    #   )
    # )
  )
}

###= "Busy Indicator" button for server

# Call this function from the server with the button id that is clicked and the
# expression to run when the button is clicked
withBusyIndicatorServer <- function(buttonId, expr) {
  # UX stuff: show the "busy" message, hide the other messages, disable the button
  loadingEl <- sprintf("[data-for-btn=%s] .btn-loading-indicator", buttonId)
  doneEl <- sprintf("[data-for-btn=%s] .btn-done-indicator", buttonId)
  # errEl <- sprintf("[data-for-btn=%s] .btn-err", buttonId)
  shinyjs::disable(buttonId)
  shinyjs::show(selector = loadingEl)
  shinyjs::hide(selector = doneEl)
  # shinyjs::hide(selector = errEl)
  on.exit({
    shinyjs::enable(buttonId)
    shinyjs::hide(selector = loadingEl)
  })

  # Try to run the code when the button is clicked and show an error message if
  # an error occurs or a success message if it completes
  tryCatch({
    value <- expr
    shinyjs::show(selector = doneEl)
    shinyjs::delay(ms = 2000,
                   expr = shinyjs::hide(selector = doneEl,
                                        anim = TRUE,
                                        animType = "fade",
                                        time = 0.5))
    value
  }# , error = function(err) { errorFunc(err, buttonId) }
  )
}

# # When an error happens after a button click, show the error
# errorFunc <- function(err, buttonId) {
#   errEl <- sprintf("[data-for-btn=%s] .btn-err", buttonId)
#   errElMsg <- sprintf("[data-for-btn=%s] .btn-err-msg", buttonId)
#   errMessage <- gsub("^ddpcr: (.*)", "\\1", err$message)
#   shinyjs::html(html = errMessage, selector = errElMsg)
#   shinyjs::show(selector = errEl, anim = TRUE, animType = "fade")
# }