I can see in the Network Response tab in chrome that I get a Response back with all the content of the file, but it seems that it's trying to parse the text of the csv file as a JSON object.
This would mean that your client code is the problem because it is trying to parse the response.
I don't know how is your client implemented so it's hard to say exactly what is the problem.
But this approach is given error: SyntaxError: Unexpected token 'export' at ....api\webpack:\external "@jsreport\browser-client":
Do you use some starter kit to set up webpack? I would try to import the jsreport client and find where is the problem.