add checks for var existance

Author: marceloschmidt

src/rocketchat.coffee

@@ -149,7 +149,7 @@ class RocketChatBotAdapter extends Adapter
 						edited = new Date(newmsg.editedAt.$date)
 						curts = if edited > curts then edited else curts
 					@robot.logger.info "Message receive callback id " + newmsg._id + " ts " + curts
-					@robot.logger.info "[Incoming] #{newmsg.u.username}: #{if newmsg.file? then newmsg.attachments[0].title else newmsg.msg}"
+					@robot.logger.info "[Incoming] #{newmsg.u.username}: #{if newmsg.file? then newmsg.attachments?[0]?.title else newmsg.msg}"
 
 					if curts > @lastts
 						@lastts = curts
@@ -176,7 +176,7 @@ class RocketChatBotAdapter extends Adapter
 								message = new AttachmentMessage user, attachment, attachment.title, newmsg._id
 							else
 								message = new TextMessage user, newmsg.msg, newmsg._id
-								
+
 							startOfText = if message.text.indexOf('@') == 0 then 1 else 0
 							robotIsNamed = message.text.indexOf(@robot.name) == startOfText || message.text.indexOf(@robot.alias) == startOfText
 							if isDM and not robotIsNamed