Have a config option to return a blob and not mandatory save

[mberrg]

E.g. if filename is empty then return raw blob (not call file-saver saveAS).

The reason if you want to send the excel file or store it natively on Cordova/capacitor app.

[davidramos-om]

@mberrg thanks to you.. added
https://www.npmjs.com/package/zipcelx-on-steroids