Handle case where room has no participants.

Signed-off-by: Joachim Bauch <bauch@struktur.de>

js/app.js

@@ -398,6 +398,7 @@
 				.then(function() {
 					self.stopListening(self.activeRoom, 'change:participantInCall');
 
+					var participants;
 					if (OC.getCurrentUser().uid) {
 						roomChannel.trigger('active', token);
 
@@ -406,14 +407,15 @@
 								self.activeRoom = room;
 							}
 						});
+						participants = self.activeRoom.get('participants');
 					} else {
 						// The public page supports only a single room, so the
 						// active room is already the room for the given token.
-
-						self.setRoomMessageForGuest(self.activeRoom.get('participants'));
+						participants = self.activeRoom.get('participants');
+						self.setRoomMessageForGuest(participants);
 					}
 					// Disable video when entering a room with more than 5 participants.
-					if (Object.keys(self.activeRoom.get('participants')).length > 5) {
+					if (participants && Object.keys(participants).length > 5) {
 						self.disableVideo();
 					}