Handle undefined device names

server/index.js

@@ -208,11 +208,21 @@ class Peer {
         let ua = parser(req.headers['user-agent']);
 
 
-        let deviceName = ua.os.name.replace('Mac OS', 'Mac') + ' ';
-        if (ua.device.model) {
-            deviceName += ua.device.model;
+        let deviceName = '';
+        
+        if (ua.os && ua.os.name) {
+            deviceName = ua.os.name.replace('Mac OS', 'Mac') + ' ';
+        }
+
+        if(ua.device){
+            if (ua.device.model) {
+                deviceName += ua.device.model;
+            } else {
+                deviceName += ua.browser.name;
+            }
         } else {
-            deviceName += ua.browser.name;
+            if(!deviceName)
+                deviceName = 'Unknown Device';
         }
 
         const displayName = uniqueNamesGenerator({