From c5c33c5e89358b9f84358d5b574835fe6517f483 Mon Sep 17 00:00:00 2001
From: Jackson Tian <puling.tyq@alibaba-inc.com>
Date: Thu, 16 Apr 2015 23:31:34 +0800
Subject: [PATCH] buffer: improve Buffer.byteLength(string, encoding)

When string is empty, it will running into binding also.
It make the performance is wasted.
---
 lib/buffer.js | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/buffer.js b/lib/buffer.js
index f125806622d49d..b391697fe751e7 100644
--- a/lib/buffer.js
+++ b/lib/buffer.js
@@ -276,6 +276,10 @@ function byteLength(string, encoding) {
   if (typeof(string) !== 'string')
     string = String(string);
 
+  if (string.length === 0) {
+    return 0;
+  }
+
   switch (encoding) {
     case 'ascii':
     case 'binary':