R/shinyDownloadExample.R

In keithnewman/shinyDownload: Shiny module that allows tables, plots and reports to be downloaded in Shiny

#' @title Run an example Shiny app
#' @description Demonstrate how the package methods work in an example Shiny app
#' @name shinyDownloadExample
#' @param example Character string containing the name of one of the example
#'   Shiny apps. You can choose from "ggplot", "report", "table" or "panel". The
#'   app will open in "showcase" mode, so the app's source code is also
#'   provided.
#' @details Thanks to Dean Attali for this method which was obtained from
#'   <https://deanattali.com/2015/04/21/r-package-shiny-app/>
#' @export
#' @examples
#' \dontrun{
#' # For downloading ggplot objects
#' shinyDownloadExample("ggplot")
#'
#' # For downloading compiled rmarkdown documents
#' shinyDownloadExample("report")
#'
#' # For downloading data frame objects
#' shinyDownloadExample("table")
#'
#' # Inspiration for how shinyDownload can be combined with a Bootstrap panel
#' shinyDownloadExample("panel")
#' }
shinyDownloadExample <- function(example) {
  # locate all the shiny app examples that exist
  validExamples <- list.files(system.file("shiny-examples",
                                          package = "shinyDownload"))

  validExamplesMsg <-
    paste0(
      "Valid examples are: '",
      paste(validExamples, collapse = "', '"),
      "'"
    )

  # if an invalid example is given, throw an error
  if (missing(example) || !nzchar(example) ||
        !example %in% validExamples) {
    stop(
      "Please run `runExample()` with a valid example app as an argument.\n",
      validExamplesMsg,
      call. = FALSE
    )
  }

  # find and launch the app
  appDir <- system.file("shiny-examples", example, package = "shinyDownload")
  shiny::runApp(appDir, display.mode = "showcase")
}