How To Add totals to a DT::datatable?

Question

I am trying to add totals to a data table footer. Using code from different sources, I wrote the following application using Shiny. The problem is, when I run it, the follow

Answer 1

Looks like you're using the same example program I did in shiny DataTables footer Callback sums so my solution to the footer callback issue is below. This is the easiest that I've found to manipulate on a column by column basis.

library(shiny)
library(DT)

ui <- fluidPage(

  title = 'Select Table Rows',

  hr(),

  h1('A Server-side Table'),

  fluidRow(
    column(9, DT::dataTableOutput('x3'))
  )

)


server <- function(input, output, session) {

  # server-side processing

  mtcars2 = mtcars[, 1:8]

  sketch <- htmltools::withTags(table(
                  class = "display",
                  style = "bootstrap",
                  tableHeader(colnames(mtcars2)),
                  tableFooter(colnames(mtcars2))
          ))

  output$x3 = DT::renderDataTable(DT::datatable(mtcars2,
                                                container = sketch,
                                                extensions = 'Buttons',
                                                options = list(
                                                  scrollX = TRUE,
                                                  scrollY = TRUE,
                                                  pageLength = 10,
                                                  order = list(list(1, 'asc')),
                                                  dom = 'Blrtip',
                                                  buttons = c('copy', 'csv', 'excel', 'pdf', 'print'),
                                                  footerCallback = JS(
       "function( tfoot, data, start, end, display ) {",
       "var api = this.api(), data;",
        "total = api.column( 1, { page: 'current'} ).data().reduce( function ( a, b ) {return a + b;} )",
        "total1 = api.column( 2, { page: 'current'} ).data().reduce( function ( a, b ) {return a + b;} )",
       "total2 = api.column( 3, { page: 'current'} ).data().reduce( function ( a, b ) {return a + b;} )",
        "total3 = api.column( 4, { page: 'current'} ).data().reduce( function ( a, b ) {return a + b;} )",
       "total4 = api.column( 5, { page: 'current'} ).data().reduce( function ( a, b ) {return a + b;} )",
        "total5 = api.column( 6, { page: 'current'} ).data().reduce( function ( a, b ) {return a + b;} )",
       "total6 = api.column( 7, { page: 'current'} ).data().reduce( function ( a, b ) {return a + b;} )",
        "total7 = api.column( 8, { page: 'current'} ).data().reduce( function ( a, b ) {return a + b;} )",
        "$( api.column( 1 ).footer() ).html(total.toFixed(2));
        $( api.column( 2 ).footer() ).html(total1.toFixed(2));
        $( api.column( 3 ).footer() ).html(total2.toFixed(2));
        $( api.column( 4 ).footer() ).html(total3.toFixed(2));
        $( api.column( 5 ).footer() ).html(total4.toFixed(2));
        $( api.column( 6 ).footer() ).html(total5.toFixed(2));
        $( api.column( 7 ).footer() ).html(total6.toFixed(2));
        $( api.column( 8 ).footer() ).html(total7.toFixed(2));",
        "}"
        ))
      ))
}

shinyApp(ui = ui, server = server)