From 27be963343cd1804b7ced0e243de5a92332a2f23 Mon Sep 17 00:00:00 2001
From: Mathias Bynens <mathias@qiwi.be>
Date: Thu, 26 Aug 2021 08:01:44 +0200
Subject: [PATCH] util: simplify util.toUSVString

Refs: https://github.com/nodejs/node/pull/39814
---
 lib/internal/util.js       |  3 +--
 test/parallel/test-util.js | 12 +++++++++++-
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/lib/internal/util.js b/lib/internal/util.js
index 34c210f27d7f7a..b4b27cefb98a3c 100644
--- a/lib/internal/util.js
+++ b/lib/internal/util.js
@@ -57,8 +57,7 @@ const experimentalWarnings = new SafeSet();
 
 const colorRegExp = /\u001b\[\d\d?m/g; // eslint-disable-line no-control-regex
 
-const unpairedSurrogateRe =
-  /(?:[^\uD800-\uDBFF]|^)[\uDC00-\uDFFF]|[\uD800-\uDBFF](?![\uDC00-\uDFFF])/;
+const unpairedSurrogateRe = /\p{Surrogate}/u;
 function toUSVString(val) {
   const str = `${val}`;
   // As of V8 5.5, `str.search()` (and `unpairedSurrogateRe[@@search]()`) are
diff --git a/test/parallel/test-util.js b/test/parallel/test-util.js
index 42218be8581579..739bd5d238583c 100644
--- a/test/parallel/test-util.js
+++ b/test/parallel/test-util.js
@@ -148,7 +148,17 @@ assert.strictEqual(util.isFunction(function() {}), true);
 assert.strictEqual(util.isFunction(), false);
 assert.strictEqual(util.isFunction('string'), false);
 
-assert.strictEqual(util.toUSVString('string\ud801'), 'string\ufffd');
+// Lead surrogates: D800..DBFF
+assert.strictEqual(util.toUSVString('string\ud800'), 'string\ufffd');
+assert.strictEqual(util.toUSVString('string\udabc'), 'string\ufffd');
+assert.strictEqual(util.toUSVString('string\udbff'), 'string\ufffd');
+// Trail surrogates: DC00..DFFF
+assert.strictEqual(util.toUSVString('string\udc00'), 'string\ufffd');
+assert.strictEqual(util.toUSVString('string\ude12'), 'string\ufffd');
+assert.strictEqual(util.toUSVString('string\udfff'), 'string\ufffd');
+// Verify surrogate pairs are unaffected.
+assert.strictEqual(util.toUSVString('string\ud800\udc00'),
+                   'string\ud800\udc00');
 
 {
   assert.strictEqual(util.types.isNativeError(new Error()), true);