util: add fast path to stripVTControlCharacters

privatenumber · aduh95 · commit 192c0382f4e4 · 2026-02-28T12:06:58.000+01:00
PR-URL: #61833 Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Colin Ihrig <cjihrig@gmail.com> Reviewed-By: Chemi Atlow <chemi@atlow.co.il> Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com> Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
diff --git a/benchmark/util/strip-vt-control-characters.js b/benchmark/util/strip-vt-control-characters.js
@@ -0,0 +1,36 @@
+'use strict';
+
+const common = require('../common.js');
+
+const { stripVTControlCharacters } = require('node:util');
+const assert = require('node:assert');
+
+const bench = common.createBenchmark(main, {
+  input: ['noAnsi-short', 'noAnsi-long', 'ansi-short', 'ansi-long'],
+  n: [1e6],
+});
+
+function main({ input, n }) {
+  let str;
+  switch (input) {
+    case 'noAnsi-short':
+      str = 'This is a plain text string without any ANSI codes';
+      break;
+    case 'noAnsi-long':
+      str = 'Long plain text without ANSI. '.repeat(333);
+      break;
+    case 'ansi-short':
+      str = '\u001B[31mHello\u001B[39m';
+      break;
+    case 'ansi-long':
+      str = ('\u001B[31m' + 'colored text '.repeat(10) + '\u001B[39m').repeat(10);
+      break;
+  }
+
+  bench.start();
+  for (let i = 0; i < n; i++) {
+    const result = stripVTControlCharacters(str);
+    assert.ok(typeof result === 'string');
+  }
+  bench.end(n);
+}
diff --git a/lib/internal/util/inspect.js b/lib/internal/util/inspect.js
@@ -3016,6 +3016,13 @@ if (internalBinding('config').hasIntl) {
 function stripVTControlCharacters(str) {
   validateString(str, 'str');
 
+  // Short-circuit: all ANSI escape sequences start with either
+  // ESC (\u001B, 7-bit) or CSI (\u009B, 8-bit) introducer.
+  // If neither is present, the string has no VT control characters.
+  if (StringPrototypeIndexOf(str, '\u001B') === -1 &&
+      StringPrototypeIndexOf(str, '\u009B') === -1)
+    return str;
+
   return RegExpPrototypeSymbolReplace(ansi, str, '');
 }
 
diff --git a/test/parallel/test-util.js b/test/parallel/test-util.js
@@ -87,3 +87,13 @@ assert.throws(() => {
   message: 'The "str" argument must be of type string.' +
            common.invalidArgTypeHelper({})
 });
+
+// stripVTControlCharacters: fast path returns input when no ANSI codes
+assert.strictEqual(util.stripVTControlCharacters('hello'), 'hello');
+assert.strictEqual(util.stripVTControlCharacters(''), '');
+
+// stripVTControlCharacters: strips 7-bit ESC sequences
+assert.strictEqual(util.stripVTControlCharacters('\u001B[31mfoo\u001B[39m'), 'foo');
+
+// stripVTControlCharacters: strips 8-bit CSI sequences
+assert.strictEqual(util.stripVTControlCharacters('\u009B31mfoo\u009B39m'), 'foo');
