upgrading serial lib

js/serial.js

@@ -10,6 +10,7 @@ var serial = {
         var self = this;
         
         chrome.serial.connect(path, options, function(connectionInfo) {
+            if (connectionInfo !== undefined) {
                 self.connectionId = connectionInfo.connectionId;
                 self.bytes_received = 0;
                 self.bytes_sent = 0;
@@ -18,11 +19,13 @@ var serial = {
                     self.bytes_received += info.data.byteLength;
                 });
                 
-            if (connectionInfo.connectionId > 0) {
                 console.log('SERIAL: Connection opened with ID: ' + connectionInfo.connectionId + ', Baud: ' + connectionInfo.bitrate);
-            }
                 
                 callback(connectionInfo);
+            } else {
+                console.log('SERIAL: Failed to open serial port');
+                callback(false);
+            }
         });
     },
     disconnect: function(callback) {