TypeError: Cannot read property 'v' of null

This is my solution that you can change in the library
On line 128 you should change the validation.

var cell = (data[R][C] && typeof data[R][C] == 'object' ? data[R][C] : { v: data[R][C] });
if (cell.v === null) continue;

instead of

var cell = (typeof data[R][C] == 'object' ? data[R][C] : { v: data[R][C] });
if (cell.v == null) continue;

because the error of a null cell value stop the execution process and does not generate the Excel file