Allow leading dot for domain (#174)

Author: blakeembrey

index.js

@@ -64,9 +64,15 @@ var cookieValueRegExp = /^("?)[\u0021\u0023-\u002B\u002D-\u003A\u003C-\u005B\u00
  * <letter> = any one of the 52 alphabetic characters A through Z in
  * upper case and a through z in lower case
  * <digit> = any one of the ten digits 0 through 9
+ *
+ * Keep support for leading dot: https://github.com/jshttp/cookie/issues/173
+ *
+ * > (Note that a leading %x2E ("."), if present, is ignored even though that
+ * character is not permitted, but a trailing %x2E ("."), if present, will
+ * cause the user agent to ignore the attribute.)
  */
 
-var domainValueRegExp = /^([a-z0-9]([a-z0-9-]{0,61}[a-z0-9])?)([.][a-z0-9]([a-z0-9-]{0,61}[a-z0-9])?)*$/i;
+var domainValueRegExp = /^([.]?[a-z0-9]([a-z0-9-]{0,61}[a-z0-9])?)([.][a-z0-9]([a-z0-9-]{0,61}[a-z0-9])?)*$/i;
 
 /**
  * RegExp to match path-value in RFC 6265 sec 4.1.1

test/serialize.js

@@ -76,6 +76,9 @@ describe('cookie.serialize(name, value, options)', function () {
  var validDomains = [
  'example.com',
  'sub.example.com',
+ '.example.com',
+ 'localhost',
+ '.localhost',
  'my-site.org',
  'localhost'
  ];
@@ -94,7 +97,6 @@ describe('cookie.serialize(name, value, options)', function () {
  'sub.example.com\u0000',
  'my site.org',
  'domain..com',
- '.example.com',
  'example.com; Path=/',
  'example.com /* inject a comment */'
  ];