In Bryntum docs I've found PDF exporter and experimental EXCEL exporter.
Is there are any way to export data in .csv format?
Not yet, but that would be very easy to implement actually. We have this ticket open to investigate it https://github.com/bryntum/support/issues/4061
You could also try to implement it yourself.
You'll need to review lib/Grid/feature/experimental/ExcelExporter.js file.
We use https://www.npmjs.com/package/zipcelx to create .xlsx file. All collected data are available in ExcelExporter feature.
You'll need to extend it and implement own export
method.
I've opened a feature request to support that https://github.com/bryntum/support/issues/5612
All the best,
Alex