Fix logging regular expression objects

Author: chasenlehara

examples/regular-expressions.js

@@ -0,0 +1,7 @@
+var winston = require('../');
+
+console.info(new RegExp('a'));
+// prints "/a/"
+
+winston.info(new RegExp('a'));
+// prints "info: /a/"

lib/winston/logger.js

@@ -124,7 +124,7 @@ Logger.prototype.log = function (level) {
   }
 
   var callback = typeof args[args.length - 1] === 'function' ? args.pop() : null,
-      meta     = typeof args[args.length - 1] === 'object' ? args.pop() : {},
+      meta     = typeof args[args.length - 1] === 'object' && Object.prototype.toString.call(args[args.length - 1]) !== '[object RegExp]' ? args.pop() : {},
       msg      = util.format.apply(null, args);
 
   // If we should pad for levels, do so

test/logger-test.js

@@ -356,6 +356,17 @@ vows.describe('winton/logger').addBatch({
           assert.strictEqual(msg, 'test message first second');
           assert.deepEqual(meta, {number: 123});
         },
+      },
+      "when passed a regular expression": {
+        topic: function (logger) {
+          var that = this;
+          logger.log('info', new RegExp('a'), function(transport, level, msg, meta){
+            that.callback(transport, level, msg, meta)
+          });
+        },
+        "should return a string representing the regular expression": function (transport, level, msg, meta) {
+          assert.strictEqual(msg, '/a/');
+        },
       }
     }
   }