lib: avoid recompilation of anonymous functions

Since at least V8 5.4, using function.bind() is now fast enough to
use to avoid recompiling/reoptimizing the same anonymous functions.
These changes especially impact http servers.

PR-URL: https://github.com/nodejs/node/pull/6533
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Fedor Indutny <fedor.indutny@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/lib/_http_outgoing.js b/lib/_http_outgoing.js
index 8d134ecc50..5a9e34bedd 100644
--- a/lib/_http_outgoing.js
+++ b/lib/_http_outgoing.js
@@ -545,6 +545,9 @@ OutgoingMessage.prototype.addTrailers = function addTrailers(headers) {
 
 const crlf_buf = Buffer.from('\r\n');
 
+function onFinish(outmsg) {
+  outmsg.emit('finish');
+}
 
 OutgoingMessage.prototype.end = function end(data, encoding, callback) {
   if (typeof data === 'function') {
@@ -592,9 +595,7 @@ OutgoingMessage.prototype.end = function end(data, encoding, callback) {
   if (typeof callback === 'function')
     this.once('finish', callback);
 
-  const finish = () => {
-    this.emit('finish');
-  };
+  var finish = onFinish.bind(undefined, this);
 
   var ret;
   if (this._hasBody && this.chunkedEncoding) {