From 4f3d25c4c577a5e12b384696e225c12dfc0b6eb6 Mon Sep 17 00:00:00 2001
From: trevor-signal <131492920+trevor-signal@users.noreply.github.com>
Date: Mon, 16 Mar 2026 13:21:35 -0700
Subject: [PATCH] Fix optimization path for unicodeSlice

---
 ts/test-node/util/unicodeSlice_test.node.ts | 1 +
 ts/util/unicodeSlice.std.ts                 | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/ts/test-node/util/unicodeSlice_test.node.ts b/ts/test-node/util/unicodeSlice_test.node.ts
index 76abc606c9..04efae568c 100644
--- a/ts/test-node/util/unicodeSlice_test.node.ts
+++ b/ts/test-node/util/unicodeSlice_test.node.ts
@@ -31,6 +31,7 @@ describe('unicodeSlice()', () => {
   test('multi-byte char', 'x€x', 1, 4, '€', 3);
   test('multi-byte char slice before end', '€', 1, 3, '', 0);
   test('multi-byte char slice after start', '€', 2, 4, '', 0);
+  test('ignores utf-16 length', '€123', 0, 4, '€1', 4);
 
   test('emoji', 'x👩‍👩‍👧‍👦x', 1, 26, '👩‍👩‍👧‍👦', 25);
   test('emoji slice before end', 'x👩‍👩‍👧‍👦x', 1, 25, '', 0);
diff --git a/ts/util/unicodeSlice.std.ts b/ts/util/unicodeSlice.std.ts
index 1295ce7648..e55dd134fe 100644
--- a/ts/util/unicodeSlice.std.ts
+++ b/ts/util/unicodeSlice.std.ts
@@ -21,7 +21,7 @@ export function unicodeSlice(
   end: number
 ): string {
   // Optimization: whole string fits into the range, return as is
-  if (begin === 0 && end >= input.length) {
+  if (begin === 0 && end >= Buffer.byteLength(input)) {
     return input;
   }