Export HTML table to CSV using javascript.

export_table_to_csv.coffee

$("#btnExportHTMLToCSV").click((event) ->
    $table = $("#tableToExport")
    if !$table
      return false
    headers = []
    csv = ""
    $table.find("thead th").each(() ->
      $th = $(this)
      text = $th.text()
      header = '"'+text+'"'
      headers.push(header)
    )
    csv += headers.join(',')+"\n"
    $table.find("tbody tr").each(() ->
      tdIndex = 0
      $(this).find("td").each(() ->
        row = $(this).html()
        tdIndex += 1
        if(tdIndex < 4)
          row += ','
        else
          row += "\n"
          tdIndex = 1
        csv += row
        console.log(tdIndex)
      )
    )

#    Delete the line below in production
    console.log(csv)

#    Change the '/export/' to the url
#    You need to pass the GET parameters to the client
#      with CSV headers. Maybe you want to encode it
#      before sending it.
    window.open(location.origin+"/export/"+csv)
)

thanks a lot. this really helped me brush up on my vanila javascript. here's a suggestion to improve this you could have something like this:
$table.getElementsByTagName('tr').forEach(element => { tdIndex = 0; element.getElementsByTagName('td').forEach(tdElement => { row = tdElement.innerText; tdIndex += 1; if (tdIndex < headers.length) { row += ','; } else{ row += '\n'; tdIndex =1 } csv += row; }) })
note: headers was defined in an earlier line from the original code...