vCard-js not allowing dynamic fields

I'm trying to create a .vcf card using vCard-js in my Node/Express project.

I'm pulling from an end-point that has multiple phone, email and addresses.

I'm trying to do a simple loop through the files and create a unique label for each, but I'm not able to set it up.

Here is what I have:

  for(i=0; i < req.body.emails.length; i++){
    vCard.req.body.emails[i].email_type = req.body.emails[i].email_address;
  }

Does anyone have experience with this?

via cnak2