Create createHost thing.

client/peer.js

@@ -2,6 +2,58 @@ function errorHandler(error) {
     console.log(error);
 }
 
+export function createHost(peerExchange, peerConnectionConfig) {
+    const listeners = new Set();
+
+    function onConnection(callback) {
+        listeners.push(callback);
+    }
+
+    function emitConnection(conn) {
+        listeners.forEach(callback => callback(conn));
+    }
+
+    function handleSDP(sdp) {
+        host.setRemoteDescription(new RTCSessionDescription(signal.sdp));
+    }
+
+    peerExchange.listen(async (signal, send) => {
+        if (signal.sdp && signal.sdp.type === "offer") {
+            const host = createConn(peerExchange, peerConnectionConfig);
+
+            const remoteDesc = new RTCSessionDescription(signal.sdp);
+            await host.setRemoteDescription(remoteDesc);
+
+            const localDesc = await conn.createAnswer();
+            await host.setLocalDescription(localDesc);
+
+            send({'sdp': desc});
+        }
+    });
+
+    return {
+        onConnection,
+    };
+}
+
+export function createConn(peerExchange, peerConnectionConfig) {
+    const conn = new RTCPeerConnection(peerConnectionConfig);
+
+    conn.addEventListener('icecandidate', event => {
+        if(event.candidate != null) {
+            peerExchange.send({ice: event.candidate});
+        }
+    });
+
+    peerExchange.listen(signal => {
+        if(signal.ice) {
+            conn.addIceCandidate(new RTCIceCandidate(signal.ice)).catch(errorHandler);
+        }
+    });
+
+    return conn;
+}
+
 export function createPeer(peerExchange, peerConnectionConfig) {
     const conn = new RTCPeerConnection(peerConnectionConfig);