perf(webidl/ByteString): 3x faster ASCII check (#12230)

1 files changed, 4 insertions, 7 deletions

diff --git a/ext/webidl/00_webidl.js b/ext/webidl/00_webidl.js
index 0b8d5c03d..88384406a 100644
--- a/ext/webidl/00_webidl.js
+++ b/ext/webidl/00_webidl.js
@@ -62,7 +62,6 @@
     String,
     StringFromCodePoint,
     StringPrototypeCharCodeAt,
-    StringPrototypeCodePointAt,
     Symbol,
     SymbolIterator,
     SymbolToStringTag,
@@ -375,15 +374,13 @@
     return String(V);
   };
 
+  // deno-lint-ignore no-control-regex
+  const IS_BYTE_STRING = /^[\x00-\xFF]*$/;
   converters.ByteString = (V, opts) => {
     const x = converters.DOMString(V, opts);
-    let c;
-    for (let i = 0; (c = StringPrototypeCodePointAt(x, i)) !== undefined; ++i) {
-      if (c > 255) {
-        throw makeException(TypeError, "is not a valid ByteString", opts);
-      }
+    if (!RegExpPrototypeTest(IS_BYTE_STRING, x)) {
+      throw makeException(TypeError, "is not a valid ByteString", opts);
     }
-
     return x;
   };