From 513ffb32e5a8065de368ccab22ee71986d3946e0 Mon Sep 17 00:00:00 2001
From: Nikolai Vavilov <vvnicholas@gmail.com>
Date: Sun, 5 Feb 2017 14:14:53 +0200
Subject: [PATCH] buffer: stricter argument checking in toString

This prevents the confusing behavior of `buf.toString(0, 5)` by
disallowing passing `0` as the encoding.

PR-URL: https://github.com/nodejs/node/pull/11120
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
---
 lib/buffer.js                               | 2 +-
 test/parallel/test-buffer-tostring-range.js | 8 ++++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/lib/buffer.js b/lib/buffer.js
index 0a8724bda48e48..cb93d7e2488f3b 100644
--- a/lib/buffer.js
+++ b/lib/buffer.js
@@ -463,7 +463,7 @@ function slowToString(encoding, start, end) {
   if (end <= start)
     return '';
 
-  if (!encoding) encoding = 'utf8';
+  if (encoding === undefined) encoding = 'utf8';
 
   while (true) {
     switch (encoding) {
diff --git a/test/parallel/test-buffer-tostring-range.js b/test/parallel/test-buffer-tostring-range.js
index c7ab356e4661ff..a550906912a480 100644
--- a/test/parallel/test-buffer-tostring-range.js
+++ b/test/parallel/test-buffer-tostring-range.js
@@ -82,3 +82,11 @@ assert.strictEqual(rangeBuffer.toString('ascii', 0, true), 'a');
 assert.strictEqual(rangeBuffer.toString({toString: function() {
   return 'ascii';
 }}), 'abc');
+
+// try toString() with 0 and null as the encoding
+assert.throws(() => {
+  rangeBuffer.toString(0, 1, 2);
+}, /^TypeError: Unknown encoding: 0$/);
+assert.throws(() => {
+  rangeBuffer.toString(null, 1, 2);
+}, /^TypeError: Unknown encoding: null$/);