Shiny: trigger datatable export button with custom button

Question

I want to trigger the csv-export button of a data table with a custom actionButton in the sidebar of shinydashboard.

However, I do not get it working since the pressed actionButton does not start the download. Could someone please help me with this problem?

And is it possible to hide the csv-export button in the data table?

library(DT)
library(shiny)
library(shinyjs)
library(shinydashboard)
library(shinydashboardPlus)

ui <- 
   shinydashboard::dashboardPage(
      shinydashboard::dashboardHeader(),
      shinydashboard::dashboardSidebar(
         shinydashboard::menuItem(
           tabName = NULL,
           icon = shiny::icon("download"),
           text = "Export data set"
         ),
         shiny::tags$div(
           id = "sidebar-table-buttons",  # necessary to reference to in javascript function
           shiny::actionButton("button_export_datatable_csv",
                               label = "csv"),
         )
      ),
      shinydashboard::dashboardBody(
         shinyjs::useShinyjs(),
         shiny::fluidRow(
           shinydashboardPlus::box(
              DT::dataTableOutput("dt_mtcars"),
              width = 12,
              height = 12
           )
         )
      )
   )

server <- 
   function(input, output, session) {  
      output$dt_mtcars =
         DT::renderDataTable(
            DT::datatable(
               mtcars,
               selection = "single",
               editable = FALSE,
               extensions = "Buttons",
               options = list(dom = "Bt",
                              buttons = c("csv"),
                              paging = TRUE
               )
            ),
            server = FALSE
         )
      
      observeEvent(
         input$button_export_datatable_csv,
         JS("$('.buttons-csv').trigger('click');")
      )
   }

shiny::shinyApp(ui, server)

Answer 1

You cannot run JavaScript server-side without sending a message to the client (UI) using session$sendCustomMessage(). Here, we can use the actionButton()'s onclick method to execute the JavaScript without having to use the server at all.

shiny::actionButton(
  "button_export_datatable_csv",
  label = "csv", 
  # Click the CSV button when the button is pressed
  onclick = "$('.buttons-csv').trigger('click');"
)

To hide the original button, you can use some CSS.

tags$head(tags$style(
  rel = "stylesheet",
  ".buttons-csv {
     display: none !important;
   }"
))

Here is the full code:

library(DT)
library(shiny)
library(shinyjs)
library(shinydashboard)
library(shinydashboardPlus)

ui <- 
  shinydashboard::dashboardPage(
    shinydashboard::dashboardHeader(),
    shinydashboard::dashboardSidebar(
      shinydashboard::menuItem(
        tabName = NULL,
        icon = shiny::icon("download"),
        text = "Export data set"
      ),
      shiny::tags$div(
        id = "sidebar-table-buttons",  # necessary to reference to in javascript function
        shiny::actionButton("button_export_datatable_csv",
                            label = "csv", 
                            # Click the CSV button when the button is pressed
                            onclick = "$('.buttons-csv').trigger('click');"),
      )
    ),
    shinydashboard::dashboardBody(
      # Custom CSS to disable download button
      tags$head(tags$style(
        rel = "stylesheet",
        ".buttons-csv {
          display: none !important;
        }"
      )),
      shinyjs::useShinyjs(),
      shiny::fluidRow(
        shinydashboardPlus::box(
          DT::dataTableOutput("dt_mtcars"),
          width = 12,
          height = 12
        )
      )
    )
  )

server <- 
  function(input, output, session) {  
    output$dt_mtcars =
      DT::renderDataTable(
        DT::datatable(
          mtcars,
          selection = "single",
          editable = FALSE,
          extensions = "Buttons",
          options = list(dom = "Bt",
                         buttons = c("csv"),
                         paging = TRUE
          )
        ),
        server = FALSE
      )
  }

shiny::shinyApp(ui, server)