DT R Shiny-添加标题边框

Question

I would like to add a top border to the header of a DataTable output in a Shiny App so that it follows the format you'd see in a typical journal article. Example of desired table format: desired format

Here is where I stand:

 output$core_metrics <- renderDataTable(core_metrics(), rownames = F,
                                       options = list(
                                         dom = 't',
                                         class = 'compact',
                                         columnDefs = list(list(className = 'dt-center', targets = "_all")),
                                         initComplete = JS("function(settings, json) {$(this.api().table().header()).css({
                                                           'border-top' : '5px solid black'});}")

I am able to change other aspects of the header column, such as font size, but none of the border calls function. I know next to nothing about CSS and I expect that perhaps I need to change or add to the .header() part of the expression? Thank you for your time!

Answer 1

library(DT)

headerCallback <- c(
  "function(thead, data, start, end, display){",
  "  $('th', thead).css('border-top', '5px solid black');",
  "}"
)

datatable(iris, rownames = FALSE, 
          options = list(
            headerCallback = JS(headerCallback)
          )
)