DataTables: Cannot read property 'length' of undefined

Question

I understand this a popular issue, and I have read all the similar questions here on Stack Overflow and other sites (including the datatables website).

To clarify, I

Answer 1

It's even simpler: just use dataSrc:'' option in the ajax defintion so dataTable knows to expect an array instead of an object:

    $('#pos-table2').DataTable({
                  processing: true,
                  serverSide: true,
                  ajax:{url:"pos.json",dataSrc:""}
            }
    );

See ajax options