From c36b2d8fdcbe91401d0788574bfbf5e716ef1b4f Mon Sep 17 00:00:00 2001
From: Punyapal Shah <53343069+MrPunyapal@users.noreply.github.com>
Date: Thu, 5 Nov 2026 02:15:26 +0530
Subject: [PATCH] perf: reuse the changelog calendar date formatter

---
 resources/js/lib/changelog.ts | 8 +++++---
 tests/Unit/Changelog.test.ts  | 9 +++++++++
 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/resources/js/lib/changelog.ts b/resources/js/lib/changelog.ts
index a4df9a826..ae712a180 100644
--- a/resources/js/lib/changelog.ts
+++ b/resources/js/lib/changelog.ts
@@ -43,12 +43,14 @@ export function changelogDays(
     timeZone: string,
 ): ChangelogDay[] {
     const days: ChangelogDay[] = [];
+    const calendar = new Intl.DateTimeFormat('en-CA', { timeZone });
     let seenAuthors = new Set<string>();
 
     for (const commit of commits) {
-        const date = new Date(commit.committed_at).toLocaleDateString('en-CA', {
-            timeZone,
-        });
+        const parsed = new Date(commit.committed_at);
+        const date = Number.isNaN(parsed.getTime())
+            ? 'Invalid Date'
+            : calendar.format(parsed);
         let day = days.at(-1);
 
         if (day?.date !== date) {
diff --git a/tests/Unit/Changelog.test.ts b/tests/Unit/Changelog.test.ts
index b8b7d7542..87f6a96b6 100644
--- a/tests/Unit/Changelog.test.ts
+++ b/tests/Unit/Changelog.test.ts
@@ -105,3 +105,12 @@ void test('keeps the first author occurrence even for many commits on the same d
     assert.equal(days[0].commits.length, 200);
     assert.deepEqual(days[0].authors.map(({ login }) => login), ['alice', 'bob']);
 });
+
+void test('keeps grouping when a commit has an invalid timestamp', () => {
+    const days = changelogDays(
+        [commit(1, 'not-a-date', 'alice'), commit(2, '2026-10-18T03:30:00Z', 'bob')],
+        'Europe/Budapest',
+    );
+
+    assert.deepEqual(days.map((day) => day.date), ['Invalid Date', '2026-10-18']);
+});