What library is used to handle PDFs in Node JS? BAD_PDF_FILE_TYPE

I have an application that takes a pdf and uploads to Adobe's cloud services for pdf manipulation (ExtractPDF REST API). 

I'm using multer middleware (NodeJS) to receive the file from the client (ReactJS), however it changes the type of the file from application/pdf to multipart/form-data. 

This results in a failed response with code: "BAD_PDF_FILE_TYPE"

How can I receive a pdf to my server and also send it as a proper file type (application/pdf)?

Thank you,