Save react-pdf rendered file to state for sending it to server

So I am using react-pdf/renderer to generate a pdf on React client side. Now when the user presses a button, the generated file should be sent to the server as a file.

Now I am using pdf provided by the react-pdf/renderer

 setFile(pdf(<PdfReport/>))

this gives the error cannot convert object to primitive types when I append this file to formdata. I converted this file to blob and then to a file

 setFile(pdf(<PdfReport/>).toBlob());
 var pdf = new File([file], "filename");

and when I send this to the server, I get a pdf file with only this

[object Promise]

I don't know how to convert the pdf generated to file to be able to send to server.