From 4cc03e5b71240ece26ba1424cabcf35b8a939c56 Mon Sep 17 00:00:00 2001
From: snowwwz <61674849+snowwwz@users.noreply.github.com>
Date: Wed, 30 Jul 2025 06:43:28 +0900
Subject: [PATCH] Fix offset formatting in ISO strings for format=basic (#1660)

---
 src/datetime.js              | 8 ++++++--
 test/datetime/format.test.js | 1 +
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/datetime.js b/src/datetime.js
index 40a3f5511..7ea16cec1 100644
--- a/src/datetime.js
+++ b/src/datetime.js
@@ -280,12 +280,16 @@ function toISOTime(
     } else if (o.o < 0) {
       c += "-";
       c += padStart(Math.trunc(-o.o / 60));
-      c += ":";
+      if (extended) {
+        c += ":";
+      }
       c += padStart(Math.trunc(-o.o % 60));
     } else {
       c += "+";
       c += padStart(Math.trunc(o.o / 60));
-      c += ":";
+      if (extended) {
+        c += ":";
+      }
       c += padStart(Math.trunc(o.o % 60));
     }
   }
diff --git a/test/datetime/format.test.js b/test/datetime/format.test.js
index 8d0baa3c5..20efe0fab 100644
--- a/test/datetime/format.test.js
+++ b/test/datetime/format.test.js
@@ -280,6 +280,7 @@ test("DateTime#toISOTime() can omit the offset", () => {
 
 test("DateTime#toISOTime() can output the basic format", () => {
   expect(dt.toISOTime({ format: "basic" })).toBe("092354.123Z");
+  expect(dt.setZone("America/New_York").toISOTime({ format: "basic" })).toBe("052354.123-0400");
   const dt2 = dt.set({ second: 0, millisecond: 0 });
   expect(dt2.toISOTime({ format: "basic", suppressMilliseconds: true })).toBe("092300Z");
   expect(dt2.toISOTime({ format: "basic", suppressSeconds: true })).toBe("0923Z");