Live Video Stream on a Node.js Server
Try to be clear and specific.First, you are not using WebRTC here. getUserMedia() is a part of navigator WebAPI which you are using to get media stream from the camera.
Using WebRTC means you are using ICE and STUN/TURN servers for the purpose of signaling. You will use your host server(Node) for specifying ICE configuration, identify each user and provide a way to call each other.
If you want to stream it through your host, probably you should stream it in chunks and set up your own signaling infrastructure. You can use Stream API with socket io to stream data in chunks(packets). See here Stream API(socket.io)
Also, you can check out the live example of WebRTC + Socket.io here: Socket.io | WebRTC Video Chat
You can find out more information here: sending a media stream to Host server