Can you clarify the use case? For client side use, PeerJS [0] (a bit old though), simple-peer [1], and SimpleWebRTC.js [2] are friendly abstractions (and you'd use publicly-provided stun/turn servers). If you need to do more advanced stuff instead of client-to-client, there are a couple server-side impls, but it's not a common use case.

0 - http://peerjs.com/

1 - https://github.com/feross/simple-peer

2 - https://simplewebrtc.com/