finally figured out how to get & save images by group media in telegrafjs
My implementation can be found at https://gist.github.com/waptik/dff071a40d87507da497555ede8599c4 . It's mainly based on https://github.com/TGxTG/TOUGAO/blob/master/src/model/Message.js#L86
I tested it by setting up a middleware that sends me the final group msg
I tested it by setting up a middleware that sends me the final group msg