From de58d9f481e637248639f3aa1f7186f3521deb7b Mon Sep 17 00:00:00 2001
From: xiehuanyi <74809554+xiehuanyi@users.noreply.github.com>
Date: Tue, 13 Oct 2026 21:01:49 +0300
Subject: [PATCH 1/2] Preserve complete dates for expanded ISO years

---
 lib/serializer.js               |  2 +-
 test/date-expanded-year.test.js | 13 +++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)
 create mode 100644 test/date-expanded-year.test.js

diff --git a/lib/serializer.js b/lib/serializer.js
index 1b3a77d8..b58ca483 100644
--- a/lib/serializer.js
+++ b/lib/serializer.js
@@ -108,7 +108,7 @@ module.exports = class Serializer {
   asDate (date) {
     if (date === null) return '""'
     if (date instanceof Date) {
-      return '"' + new Date(date.getTime() - (date.getTimezoneOffset() * 60000)).toISOString().slice(0, 10) + '"'
+      return '"' + new Date(date.getTime() - (date.getTimezoneOffset() * 60000)).toISOString().slice(0, -14) + '"'
     }
     if (typeof date === 'string') {
       return asString(date)
diff --git a/test/date-expanded-year.test.js b/test/date-expanded-year.test.js
new file mode 100644
index 00000000..89768388
--- /dev/null
+++ b/test/date-expanded-year.test.js
@@ -0,0 +1,13 @@
+'use strict'
+
+const { test } = require('node:test')
+const build = require('..')
+
+process.env.TZ = 'UTC'
+
+for (const iso of ['+010000-02-03T04:05:06.000Z', '-000001-02-03T04:05:06.000Z', '0000-02-03T04:05:06.000Z', '9999-02-03T04:05:06.000Z']) {
+  test(`preserve the whole calendar date for ${iso}`, (t) => {
+    const stringify = build({ type: 'string', format: 'date' })
+    t.assert.equal(stringify(new Date(iso)), JSON.stringify(iso.split('T')[0]))
+  })
+}

From 24c39ea892382e930f48b59ac122fbba11696eef Mon Sep 17 00:00:00 2001
From: xiehuanyi <74809554+xiehuanyi@users.noreply.github.com>
Date: Thu, 22 Oct 2026 06:07:08 +0300
Subject: [PATCH 2/2] Fix expanded-year time serialization and consolidate date
 tests

---
 lib/serializer.js               |  2 +-
 test/date-expanded-year.test.js | 13 -------------
 test/date.test.js               | 12 ++++++++++++
 3 files changed, 13 insertions(+), 14 deletions(-)
 delete mode 100644 test/date-expanded-year.test.js

diff --git a/lib/serializer.js b/lib/serializer.js
index b58ca483..acd3cdc4 100644
--- a/lib/serializer.js
+++ b/lib/serializer.js
@@ -119,7 +119,7 @@ module.exports = class Serializer {
   asTime (date) {
     if (date === null) return '""'
     if (date instanceof Date) {
-      return '"' + new Date(date.getTime() - (date.getTimezoneOffset() * 60000)).toISOString().slice(11, 19) + '"'
+      return '"' + new Date(date.getTime() - (date.getTimezoneOffset() * 60000)).toISOString().slice(-13, -5) + '"'
     }
     if (typeof date === 'string') {
       return asString(date)
diff --git a/test/date-expanded-year.test.js b/test/date-expanded-year.test.js
deleted file mode 100644
index 89768388..00000000
--- a/test/date-expanded-year.test.js
+++ /dev/null
@@ -1,13 +0,0 @@
-'use strict'
-
-const { test } = require('node:test')
-const build = require('..')
-
-process.env.TZ = 'UTC'
-
-for (const iso of ['+010000-02-03T04:05:06.000Z', '-000001-02-03T04:05:06.000Z', '0000-02-03T04:05:06.000Z', '9999-02-03T04:05:06.000Z']) {
-  test(`preserve the whole calendar date for ${iso}`, (t) => {
-    const stringify = build({ type: 'string', format: 'date' })
-    t.assert.equal(stringify(new Date(iso)), JSON.stringify(iso.split('T')[0]))
-  })
-}
diff --git a/test/date.test.js b/test/date.test.js
index 79f21b3d..baf874e4 100644
--- a/test/date.test.js
+++ b/test/date.test.js
@@ -6,6 +6,18 @@ const build = require('..')
 
 process.env.TZ = 'UTC'
 
+for (const iso of ['+010000-02-03T04:05:06.000Z', '-000001-02-03T04:05:06.000Z', '0000-02-03T04:05:06.000Z', '9999-02-03T04:05:06.000Z']) {
+  test(`preserve the whole calendar date for ${iso}`, (t) => {
+    const stringify = build({ type: 'string', format: 'date' })
+    t.assert.equal(stringify(new Date(iso)), JSON.stringify(iso.split('T')[0]))
+  })
+
+  test(`preserve the time for ${iso}`, (t) => {
+    const stringify = build({ type: 'string', format: 'time' })
+    t.assert.equal(stringify(new Date(iso)), '"04:05:06"')
+  })
+}
+
 test('render a date in a string as JSON', (t) => {
   t.plan(2)