From 8eacd509c373e01a33227c3f48cdee96a5fe7977 Mon Sep 17 00:00:00 2001
From: ravestack <ravestack@gmail.com>
Date: Tue, 4 Aug 2015 02:22:15 -0400
Subject: [PATCH] Leap year and general date validation for isDate()

---
 test/validators.js | 11 +++++++++++
 validator.js       | 28 +++++++++++++++++++++++++++-
 2 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/test/validators.js b/test/validators.js
index 4cf642c24..10e537074 100644
--- a/test/validators.js
+++ b/test/validators.js
@@ -852,15 +852,26 @@ describe('Validators', function () {
             validator: 'isDate'
           , valid: [
                 '2011-08-04'
+              , '2011-09-30'
               , '04. 08. 2011.'
               , '08/04/2011'
               , '2011.08.04'
               , '4. 8. 2011. GMT'
+              , '2. 28. 2011. GMT'
+              , '2. 29. 2008. GMT'
+              , '2. 29. 1988. GMT'
               , '2011-08-04 12:00'
+              , '2/29/24'
+              , '2-29-24'
             ]
           , invalid: [
                 'foo'
               , '2011-foo-04'
+              , '2011-09-31'
+              , '2. 29. 1987. GMT'
+              , '2. 29. 2011. GMT'
+              , '2/29/25'
+              , '2-29-25'
               , 'GMT'
             ]
         });
diff --git a/validator.js b/validator.js
index 8d2d155e5..bb3f068f3 100644
--- a/validator.js
+++ b/validator.js
@@ -450,7 +450,33 @@
     };
 
     validator.isDate = function (str) {
-        return !isNaN(Date.parse(str));
+        var normalizedDate = new Date((new Date(str)).toUTCString());
+        var regularDay = String(normalizedDate.getDate());
+        var utcDay = String(normalizedDate.getUTCDate());
+        var dayOrYear, dayOrYearMatches, year;
+        if (isNaN(Date.parse(normalizedDate))) {
+            return false;
+        }
+        //check for valid double digits that could be late days
+        //check for all matches since a string like '12/23' is a valid date
+        dayOrYearMatches = str.match(/[23]\d(\D|$)/g);
+        if (!dayOrYearMatches) {
+            return true;
+        }
+        dayOrYear = dayOrYearMatches.map(function(match) {
+            return match.slice(0,2);
+        }).join('/');
+        year = String(normalizedDate.getFullYear()).slice(-2);
+        //local date and UTC date can differ, but both are valid, so check agains both
+        if (dayOrYear === regularDay || dayOrYear === utcDay || dayOrYear === year) {
+            return true;
+        } else if ((dayOrYear === (regularDay + '/' + year)) || (dayOrYear === (year + '/' + regularDay))) {
+            return true;
+        } else if ((dayOrYear === (utcDay + '/' + year)) || (dayOrYear === (year + '/' + utcDay))) {
+            return true;
+        } else {
+            return false;
+        }
     };
 
     validator.isAfter = function (str, date) {