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: #11120 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Joyee Cheung <[email protected]> Reviewed-By: Sakthipriyan Vairamani <[email protected]> Reviewed-By: Luigi Pinca <[email protected]>
nodejs · Feb 5, 2017 · 9a0829d · 9a0829d
1 parent 67af1ad
commit 9a0829d
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diff --git 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
@@ -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$/);
+assert.throws(() => {
+  rangeBuffer.toString(null, 1, 2);
+}, /^TypeError: Unknown encoding: null$/);