From d04246a0d73a394c5b32268fde2c22237d0f7b8f Mon Sep 17 00:00:00 2001
From: Robert Nagy <ronagy@icloud.com>
Date: Wed, 14 Aug 2024 21:46:48 +0200
Subject: [PATCH] buffer: optimize byteLength for common encodings

PR-URL: https://github.com/nodejs/node/pull/54342
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
---
 lib/buffer.js | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/lib/buffer.js b/lib/buffer.js
index 074966dd55b59b..81c0c5e2830c5c 100644
--- a/lib/buffer.js
+++ b/lib/buffer.js
@@ -780,13 +780,22 @@ function byteLength(string, encoding) {
   if (len === 0)
     return 0;
 
-  if (encoding) {
-    const ops = getEncodingOps(encoding);
-    if (ops) {
-      return ops.byteLength(string);
-    }
+  if (!encoding || encoding === 'utf8') {
+    return byteLengthUtf8(string);
+  }
+
+  if (encoding === 'ascii') {
+    return len;
   }
-  return byteLengthUtf8(string);
+
+  const ops = getEncodingOps(encoding);
+  if (ops === undefined) {
+    // TODO (ronag): Makes more sense to throw here.
+    // throw new ERR_UNKNOWN_ENCODING(encoding);
+    return byteLengthUtf8(string);
+  }
+
+  return ops.byteLength(string);
 }
 
 Buffer.byteLength = byteLength;