util: optimize toASCIILower function using V8s native toLowerCase

mertcanaltin · RafaelGSS · commit 09b53965238f · 2026-01-13T10:04:54.000-03:00
PR-URL: #61107 Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com> Reviewed-By: Anna Henningsen <anna@addaleax.net> Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
diff --git a/lib/internal/mime.js b/lib/internal/mime.js
@@ -23,6 +23,8 @@ const END_BEGINNING_WHITESPACE = /[^\r\n\t ]|$/;
 const START_ENDING_WHITESPACE = /[\r\n\t ]*$/;
 
 function toASCIILower(str) {
+  // eslint-disable-next-line no-control-regex
+  if (!/[^\x00-\x7f]/.test(str)) return StringPrototypeToLowerCase(str);
   let result = '';
   for (let i = 0; i < str.length; i++) {
     const char = str[i];
