From f7879d98f839ea867a2cb938beeb6a071294ebbe Mon Sep 17 00:00:00 2001
From: Brian White <mscdex@mscdex.net>
Date: Thu, 19 Jan 2017 02:55:21 -0500
Subject: [PATCH] buffer: improve toJSON() performance

PR-URL: https://github.com/nodejs/node/pull/10895
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Michal Zasso <targos@protonmail.com>
Reviewed-By: Evan Lucas <evanlucas@me.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
---
 benchmark/buffers/buffer-tojson.js | 18 ++++++++++++++++++
 lib/buffer.js                      | 12 ++++++++----
 2 files changed, 26 insertions(+), 4 deletions(-)
 create mode 100644 benchmark/buffers/buffer-tojson.js

diff --git a/benchmark/buffers/buffer-tojson.js b/benchmark/buffers/buffer-tojson.js
new file mode 100644
index 00000000000000..1be59952c3fe60
--- /dev/null
+++ b/benchmark/buffers/buffer-tojson.js
@@ -0,0 +1,18 @@
+'use strict';
+
+const common = require('../common.js');
+
+const bench = common.createBenchmark(main, {
+  n: [1e4],
+  len: [0, 10, 256, 4 * 1024]
+});
+
+function main(conf) {
+  var n = +conf.n;
+  var buf = Buffer.allocUnsafe(+conf.len);
+
+  bench.start();
+  for (var i = 0; i < n; ++i)
+    buf.toJSON();
+  bench.end(n);
+}
diff --git a/lib/buffer.js b/lib/buffer.js
index 84a97ea325580a..28534bab2783ad 100644
--- a/lib/buffer.js
+++ b/lib/buffer.js
@@ -785,10 +785,14 @@ Buffer.prototype.write = function(string, offset, length, encoding) {
 
 
 Buffer.prototype.toJSON = function() {
-  return {
-    type: 'Buffer',
-    data: Array.prototype.slice.call(this, 0)
-  };
+  if (this.length) {
+    const data = [];
+    for (var i = 0; i < this.length; ++i)
+      data[i] = this[i];
+    return { type: 'Buffer', data };
+  } else {
+    return { type: 'Buffer', data: [] };
+  }
 };