Fix isDate() handling of ISO8601 timezones

CHANGELOG.md

@@ -1,5 +1,7 @@
 #### HEAD
 
+- Fix `isDate()` handling of ISO8601 timezones
+  ([#444](https://github.com/chriso/validator.js/pull/444))
 - Fix the incorrect `isFloat('.') === true`
   ([#443](https://github.com/chriso/validator.js/pull/443))
 - Added a Norwegian locale to `isMobilePhone()`

test/validators.js

@@ -889,6 +889,11 @@ describe('Validators', function () {
               , '2009-05-19 14:39:22-06:00'
               , '2009-05-19 14:39:22+0600'
               , '2009-05-19 14:39:22-01'
+              , '2015-10-20T00:53:09+08:00'
+              , '2015-10-20T00:53:09+09:00'
+              , '2015-10-20T00:53:09+10:00'
+              , '2015-10-20T00:53:09+11:00'
+              , '2015-10-20T00:53:09+12:00'
               , '2007-04-06T00:00'
               , '2010-02-18T16:23:48.5'
               , '200905'

validator.js

@@ -470,10 +470,37 @@
         return pattern && pattern.test(str);
     };
 
+    function getTimezoneOffset(str) {
+        var iso8601Parts = str.match(iso8601);
+        if (!iso8601Parts) {
+            return new Date().getTimezoneOffset();
+        }
+        var timezone = iso8601Parts[21];
+        if (!timezone || timezone === 'z' || timezone === 'Z') {
+            return 0;
+        }
+        var sign = iso8601Parts[22], hours, minutes;
+        if (timezone.indexOf(':') !== -1) {
+            hours = parseInt(iso8601Parts[23]);
+            minutes = parseInt(iso8601Parts[24]);
+        } else {
+            hours = 0;
+            minutes = parseInt(iso8601Parts[23]);
+        }
+        return (hours * 60 + minutes) * (sign === '-' ? 1 : -1);
+    }
+
     validator.isDate = function (str) {
         var normalizedDate = new Date((new Date(str)).toUTCString());
-        var regularDay = String(normalizedDate.getDate());
         var utcDay = String(normalizedDate.getUTCDate());
+        // normalizedDate is in the user's timezone. Apply the input
+        // timezone offset to the date so that the year and day match
+        // the input
+        var timezoneDifference = normalizedDate.getTimezoneOffset() -
+            getTimezoneOffset(str);
+        normalizedDate = new Date(normalizedDate.getTime() +
+            60000 * timezoneDifference);
+        var regularDay = String(normalizedDate.getDate());
         var dayOrYear, dayOrYearMatches, year;
         if (isNaN(Date.parse(normalizedDate))) {
             return false;