util: add fast path to stripVTControlCharacters

Author: privatenumber

benchmark/util/strip-vt-control-characters.js

@@ -0,0 +1,37 @@
+'use strict';
+
+const common = require('../common.js');
+
+const { stripVTControlCharacters } = require('node:util');
+const assert = require('node:assert');
+
+const bench = common.createBenchmark(main, {
+  input: ['plain-short', 'plain-long', 'ansi-short', 'ansi-heavy'],
+  n: [1e6],
+});
+
+function main({ input, n }) {
+  let str;
+  switch (input) {
+    case 'plain-short':
+      str = 'Hello, World!';
+      break;
+    case 'plain-long':
+      str = 'a'.repeat(1000);
+      break;
+    case 'ansi-short':
+      str = '\u001B[31mHello\u001B[39m';
+      break;
+    case 'ansi-heavy':
+      str = '\u001B[1m\u001B[31m\u001B[4m' + 'x'.repeat(100) +
+            '\u001B[24m\u001B[39m\u001B[22m';
+      break;
+  }
+
+  bench.start();
+  for (let i = 0; i < n; i++) {
+    const result = stripVTControlCharacters(str);
+    assert.ok(typeof result === 'string');
+  }
+  bench.end(n);
+}

lib/internal/util/inspect.js

@@ -3036,6 +3036,10 @@ if (internalBinding('config').hasIntl) {
 function stripVTControlCharacters(str) {
   validateString(str, 'str');
 
+  if (!StringPrototypeIncludes(str, '\u001B') &&
+      !StringPrototypeIncludes(str, '\u009B'))
+    return str;
+
   return RegExpPrototypeSymbolReplace(ansi, str, '');
 }
 

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');