From aee0e19edc343068969aa095c1000c75a0d302da Mon Sep 17 00:00:00 2001
From: Alexandr Nikitin <nikitin.alexandr.a@gmail.com>
Date: Sun, 29 Mar 2015 11:38:17 +0300
Subject: [PATCH] Revert "Revert "Fixes #56 (Bug in %U)""

This reverts commit ab3d4a052ea48363e5c1684f5aff9d90f3ce2a30.
---
 strftime.js | 6 ++++--
 test.js     | 3 +++
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/strftime.js b/strftime.js
index 37635ab..c05c3f0 100644
--- a/strftime.js
+++ b/strftime.js
@@ -595,8 +595,10 @@
             else
                 weekday--;
         }
-        var firstDayOfYear = new Date(date.getFullYear(), 0, 1),
-            yday = (date - firstDayOfYear) / 86400000,
+
+        var firstDayOfYearUtc = Date.UTC(date.getFullYear(), 0, 1),
+            dateUtc = Date.UTC(date.getFullYear(), date.getMonth(), date.getDate()),
+            yday = Math.floor((dateUtc - firstDayOfYearUtc) / 86400000),
             weekNum = (yday + 7 - weekday) / 7;
 
         return Math.floor(weekNum);
diff --git a/test.js b/test.js
index 0b0a974..5b6fd62 100755
--- a/test.js
+++ b/test.js
@@ -115,6 +115,9 @@ assert.format('%z', null, '+0000');
 assert.format('%:z', null, '+00:00');
 assert.format('%%', '%'); // any other char
 assert.format('%F %T', null, '1970-01-01 00:00:00', new Date(0));
+assert.format('%U', '13', "12", (new Date('03-26-2017 00:00:00')));
+assert.format('%U', '13', null, (new Date('03-27-2017 00:00:00')));
+assert.format('%U', '14', "13", (new Date('04-02-2017 00:00:00')));
 ok('GMT');