From 5485ca3745ba6cc9a919a86bd5f1b4f778acdb4a Mon Sep 17 00:00:00 2001
From: Basil Goryachev <vasiliy.goryachev@lightspeedhq.com>
Date: Fri, 14 Jun 2024 03:02:38 -0300
Subject: [PATCH] fix: Wrong weekday names when using `format-locale` in
 overridden timezone

---
 src/VueDatePicker/utils/util.ts |  2 +-
 tests/unit/utils.spec.ts        | 40 ++++++++++++++++++++++++++++++---
 2 files changed, 38 insertions(+), 4 deletions(-)

diff --git a/src/VueDatePicker/utils/util.ts b/src/VueDatePicker/utils/util.ts
index ec6ca0f5..d9910f74 100644
--- a/src/VueDatePicker/utils/util.ts
+++ b/src/VueDatePicker/utils/util.ts
@@ -35,7 +35,7 @@ function dayNameIntlMapper(locale: string) {
 
 function dayNameDateFnsMapper(formatLocale: Locale) {
     return (day: number) => {
-        return format(new Date(`2017-01-0${day}T00:00:00+00:00`), 'EEEEEE', { locale: formatLocale });
+        return format(localToTz(new Date(`2017-01-0${day}T00:00:00+00:00`), 'UTC'), 'EEEEEE', { locale: formatLocale });
     };
 }
 
diff --git a/tests/unit/utils.spec.ts b/tests/unit/utils.spec.ts
index 19d89aac..aa8996c4 100644
--- a/tests/unit/utils.spec.ts
+++ b/tests/unit/utils.spec.ts
@@ -122,26 +122,60 @@ describe('Utils and date utils formatting', () => {
         expect(years[1].value).toEqual(2022);
     });
 
-    it('Should get month values according to locale', () => {
+    it('Should get long month values according to locale', () => {
         const months = getMonths(null, 'en', 'long');
 
         expect(months).toHaveLength(12);
         expect(months[0].text).toEqual('January');
+        expect(months[1].text).toEqual('February');
+        expect(months[2].text).toEqual('March');
     });
 
-    it('Should get month values according to formatLocale', () => {
+    it('Should get short month values according to locale', () => {
+        const months = getMonths(null, 'en', 'short');
+
+        expect(months).toHaveLength(12);
+        expect(months[0].text).toEqual('Jan');
+        expect(months[1].text).toEqual('Feb');
+        expect(months[2].text).toEqual('Mar');
+    });
+
+    it('Should get long month values according to formatLocale', () => {
         const months = getMonths(de, 'en', 'long');
 
         expect(months).toHaveLength(12);
         expect(months[0].text).toEqual('Januar');
+        expect(months[1].text).toEqual('Februar');
+        expect(months[2].text).toEqual('März');
     });
 
-    it('Should get month values by fallback to locale', () => {
+    it('Should get long month values by fallback to locale', () => {
         // Pass incorrect formatLocale
         const months = getMonths(null, 'de', 'long');
 
         expect(months).toHaveLength(12);
         expect(months[0].text).toEqual('Januar');
+        expect(months[1].text).toEqual('Februar');
+        expect(months[2].text).toEqual('März');
+    });
+
+    it('Should get short month values according to formatLocale', () => {
+        const months = getMonths(de, 'en', 'short');
+
+        expect(months).toHaveLength(12);
+        expect(months[0].text).toEqual('Jan');
+        expect(months[1].text).toEqual('Feb');
+        expect(months[2].text).toEqual('Mär');
+    });
+
+    it('Should get short month values by fallback to locale', () => {
+        // Pass incorrect formatLocale
+        const months = getMonths({}, 'de', 'short');
+
+        expect(months).toHaveLength(12);
+        expect(months[0].text).toEqual('Jan');
+        expect(months[1].text).toEqual('Feb');
+        expect(months[2].text).toEqual('Mär');
     });
 
     it('Should get default pattern', () => {