If anyone is looking for an alternative to PeerJS, I highly recommend simple-peer by feross: https://github.com/feross/simple-peer

I created multi party P2P audio/video chat in ~200 lines of code a while back, here it is: https://github.com/ScottyFillups/p2pchat (see room.js and all the files under client/)

Demo page is here: https://scottyfillups.io/p2pchat