Is there support for creating .rtf files using the Word JS API?

Question

I am developing a Word add-in and it doesn't look like there is support in the Word JS API to create an .rtf file and open it like you could in a COM add-in. What I am trying to do is use the contents of an .rtf file, create a new document from that, and open it in Word.

I know this method in the docs allows you to create a new document but only for the .docx file type. Is there a way to create .rtf files? And if not, will this be supported in the future?