Add better error handling (clear message) when opening port fails

Author: nylen

lib/Controller.js

@@ -33,8 +33,9 @@ function Controller(settings) {
         parser   : SerialPort.parsers.readline('\n')
     });
 
-    self.port.on('open', self._onPortOpen.bind(self));
-    self.port.on('data', self._onPortData.bind(self));
+    self.port.on('open' , self._onPortOpen.bind(self));
+    self.port.on('error', self._onPortError.bind(self));
+    self.port.on('data' , self._onPortData.bind(self));
 
     self._isFirstLine = true;
 
@@ -216,6 +217,20 @@ Controller.prototype._onPortOpen = function() {
     });
 };
 
+Controller.prototype._onPortError = function(err) {
+    var self = this;
+
+    console.error(
+        'Serial port error:  %s',
+        err.message
+    );
+    console.error(
+        'Check the serial device name and make sure it\'s connected.'
+    );
+    console.error();
+    throw err;
+};
+
 Controller.prototype._onPortData = function(line) {
     var self = this;