Data pre-processing

[robertmarney]

In English locales it is common to separate thousands by using a comma ie 1000 -> 1,000, also for readability zeros are replaced with a '-' (see jquery datatables)

If you were to feed either of these numbers into the parser a NaN error would result with warning for end user.

Consider either a global or cell specific (when data type is numeric) processor.

A quick and dirty deals with the global (not ideal as there may be legitimate string uses for ','

function makeXLSXExport(tableId) {
  let table = document.querySelector("#"+tableId);
  let tableT = table.cloneNode(true);;
  tableT.innerHTML = tableT.innerHTML.replace(/,/g,''); //replaces , globally
  tableT.innerHTML = tableT.innerHTML.replace(/>-</g,'><'); //replaces cells only containing - globally
  TableToExcel.convert(tableT);
}

[rohithb]

You can format numbers in the excel by using data-num-fmt="#,##0". However, if you add commas in the HTML table cells, it will not be parsed properly. One workaround is to create a column for the display and create another hidden column for exporting to excel.
One thing we can do is, remove the commas from the cell, which is marked as a number. That way, we don't need to create hidden cells for achieving this.

[robertmarney]

@rohithb - Yes, I was not clear, I think that is the best course of action, if the user sets the cell format as numeric strip all commas before processing.