Filter all the peerInfo topics that are undefined and then map all of them to hex string

Reviewed-on: snxraven/LinkUp-P2P-Chat#5

chatBot/includes/client.js

@@ -23,7 +23,7 @@ class Client extends EventEmitter {
       console.log(`Peers count: ${this.swarm.connections.size} (${this.swarm.peers.size})`);
 
       this.swarm.peers.forEach((peer, peerInfo) => {
-        console.log(`Peer ${peer} is in topic(s) ${[...peerInfo.topics].map(topic => topic.toString('hex'))}`);
+        console.log(`Peer ${peer} is in topic(s) ${[peerInfo.topics].filter(topic => topic).map(topic => topic.toString('hex'))}`);
       });
     });
   }