returning value from DT with javascript

Question

I'd like to add one more row to the answer posted here:

Determine if DT datatable is clicked in shiny app

Specifically I want to return the "a" field of the row that is clicked so I added

var a = table.rows[row_].cells[col].innerhtml 

but nothing happens.

Here is the code. Is it possible?

library(shiny)
library(DT)
runApp(shinyApp(
  ui = fluidPage(DT::dataTableOutput('table')),
  server = function(input, output, session) {
    output$table <- DT::renderDataTable({
      datatable(data.frame(a = c(1,2),b=c(2,3)), rownames = FALSE, selection = 'none', callback = JS("table.on('click.dt', 'td', function() {
            var row_=table.cell(this).index().row;
            var col=table.cell(this).index().column;
            var rnd= Math.random();
            var a = table.rows[row_].cells[col].innerhtml  
            var data = [row_, col, rnd,a];
           Shiny.onInputChange('rows',data );
    });")
      )}
    )

    observeEvent(input$rows, {


      print(input$rows)
      #print(Sys.time())

    })}
))

Thank you.

Answer 1

If you want to look at clicks from rows, you could use the following callback function:

callback=JS("table.on('click.dt', 'tr', function() {
    var data=table.row(this).data();
    Shiny.onInputChange('rows',data[0]);
});")

This looks at click events on row (tr) and gets the data directly then returns the value in the first column.