buffer,string_decoder: consolidate encoding validation logic

Buffer.isEncoding and string_decoder.normalizeEncoding shared
quite a bit of logic. This moves the primary logic into
internal/util. The userland modules that monkey patch Buffer.isEncoding
should still work.

PR-URL: https://github.com/nodejs/node/pull/7207
Reviewed-By: Brian White <mscdex@mscdex.net>
Reviewed-By: Trevor Norris <trev.norris@gmail.com>

1 files changed, 39 insertions, 0 deletions

diff --git a/test/parallel/test-internal-util-normalizeencoding.js b/test/parallel/test-internal-util-normalizeencoding.js
new file mode 100644
index 0000000000..9adc3753e8
--- /dev/null
+++ b/test/parallel/test-internal-util-normalizeencoding.js
@@ -0,0 +1,39 @@
+// Flags: --expose-internals
+'use strict';
+
+require('../common');
+const assert = require('assert');
+const util = require('internal/util');
+
+const tests = [
+  ['', 'utf8'],
+  ['utf8', 'utf8'],
+  ['utf-8', 'utf8'],
+  ['UTF-8', 'utf8'],
+  ['UTF8', 'utf8'],
+  ['Utf8', 'utf8'],
+  ['uTf-8', 'utf8'],
+  ['utF-8', 'utf8'],
+  ['ucs2', 'utf16le'],
+  ['UCS2', 'utf16le'],
+  ['utf16le', 'utf16le'],
+  ['utf-16le', 'utf16le'],
+  ['UTF-16LE', 'utf16le'],
+  ['UTF16LE', 'utf16le'],
+  ['binary', 'latin1'],
+  ['BINARY', 'latin1'],
+  ['latin1', 'latin1'],
+  ['base64', 'base64'],
+  ['BASE64', 'base64'],
+  ['hex', 'hex'],
+  ['HEX', 'hex'],
+  ['foo', undefined],
+  [1, undefined],
+  [false, 'utf8'],
+  [undefined, 'utf8'],
+  [[], undefined],
+];
+
+tests.forEach((i) => {
+  assert.strictEqual(util.normalizeEncoding(i[0]), i[1]);
+});