Is it possible to read and update a PPTX file using PpptxGenJS?

[CDHDeveloper]

In an app I'm currently designing,, I'd like to allow the user to add (or update) a slide in a currently existing PPTX file. Essentially the system will open the pre-existent file and add their slide to the batch. In my (admittedly brief) overview of PPTXGenJs it seems that only new creation is available. Is that true or have I overlooked something? If it is true, have you had others that have had similar needs and what advice did yo give them?

Thanks in advance,
Chris

[gitbrent]

This library only generates new presentations.

Reading existing presentations is an existing item on the Unimplemented Features page.