AK: Track byte length, rather than code point length, in Utf8View::trim

Utf8View::trim uses Utf8View::substring_view to return its result, which
requires the input to be a byte offset/length rather than code point
length.

1 files changed, 6 insertions, 0 deletions

diff --git a/Userland/Libraries/LibJS/Tests/builtins/String/String.prototype.trim.js b/Userland/Libraries/LibJS/Tests/builtins/String/String.prototype.trim.js
index d60522cad4..d5f7a0bec0 100644
--- a/Userland/Libraries/LibJS/Tests/builtins/String/String.prototype.trim.js
+++ b/Userland/Libraries/LibJS/Tests/builtins/String/String.prototype.trim.js
@@ -56,3 +56,9 @@ test("trimEnd", () => {
     expect("\r\nhello friends".trimEnd()).toBe("\r\nhello friends");
     expect("\rhello friends\r\n".trimEnd()).toBe("\rhello friends");
 });
+
+test("multi-byte code point", () => {
+    expect("_\u180E".trim()).toBe("_\u180E");
+    expect("\u180E".trim()).toBe("\u180E");
+    expect("\u180E_".trim()).toBe("\u180E_");
+});