buffer: improve Buffer.byteLength(string, encoding)

JacksonTian · JacksonTian · commit 7c00ec2694be · 2015-04-17T00:09:47.000+08:00
When string is empty, it will running into binding also.
It make the performance is wasted.
diff --git a/lib/buffer.js b/lib/buffer.js
@@ -276,6 +276,9 @@ function byteLength(string, encoding) {
   if (typeof(string) !== 'string')
     string = String(string);
 
+  if (string.length === 0)
+    return 0;
+
   switch (encoding) {
     case 'ascii':
     case 'binary':
