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 1/2] 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);

From 4d54445a454dd3998587a53b5df4e93b33824a72 Mon Sep 17 00:00:00 2001
From: Mathias Bynens <mathias@qiwi.be>
Date: Fri, 27 Aug 2021 11:16:47 +0200
Subject: [PATCH 2/2] util: improve `toUSVString` performance

---
 lib/internal/util.js | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/lib/internal/util.js b/lib/internal/util.js
index b4b27cefb98a3c..a3ecfb8837d1d3 100644
--- a/lib/internal/util.js
+++ b/lib/internal/util.js
@@ -17,10 +17,10 @@ const {
   Promise,
   ReflectApply,
   ReflectConstruct,
-  RegExpPrototypeExec,
   RegExpPrototypeTest,
   SafeMap,
   SafeSet,
+  StringPrototypeSearch,
   StringPrototypeReplace,
   StringPrototypeToLowerCase,
   StringPrototypeToUpperCase,
@@ -60,12 +60,10 @@ const colorRegExp = /\u001b\[\d\d?m/g; // eslint-disable-line no-control-regex
 const unpairedSurrogateRe = /\p{Surrogate}/u;
 function toUSVString(val) {
   const str = `${val}`;
-  // As of V8 5.5, `str.search()` (and `unpairedSurrogateRe[@@search]()`) are
-  // slower than `unpairedSurrogateRe.exec()`.
-  const match = RegExpPrototypeExec(unpairedSurrogateRe, str);
-  if (!match)
+  const index = StringPrototypeSearch(str, unpairedSurrogateRe);
+  if (index === -1)
     return str;
-  return _toUSVString(str, match.index);
+  return _toUSVString(str, index);
 }
 
 let uvBinding;