string_decoder: support typed array or data view

Refs: https://github.com/nodejs/node/issues/1826
PR-URL: https://github.com/nodejs/node/pull/22562
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>

doc/api/string_decoder.md

@@ -59,7 +59,8 @@ Creates a new `StringDecoder` instance.
 added: v0.9.3
 -->
 
-* `buffer` {Buffer} A `Buffer` containing the bytes to decode.
+* `buffer` {Buffer|TypedArray|DataView} A `Buffer`, or `TypedArray`, or
+ `DataView` containing the bytes to decode.
 * Returns: {string}
 
 Returns any remaining input stored in the internal buffer as a string. Bytes
@@ -79,10 +80,11 @@ changes:
                  character instead of one for each individual byte.
 -->
 
-* `buffer` {Buffer} A `Buffer` containing the bytes to decode.
+* `buffer` {Buffer|TypedArray|DataView} A `Buffer`, or `TypedArray`, or
+ `DataView` containing the bytes to decode.
 * Returns: {string}
 
 Returns a decoded string, ensuring that any incomplete multibyte characters at
-the end of the `Buffer` are omitted from the returned string and stored in an
+ the end of the `Buffer`, or `TypedArray`, or `DataView` are omitted from the
-internal buffer for the next call to `stringDecoder.write()` or
+ returned string and stored in an internal buffer for the next call to
-`stringDecoder.end()`.
+ `stringDecoder.write()` or `stringDecoder.end()`.

lib/string_decoder.js

@@ -73,7 +73,7 @@ StringDecoder.prototype.write = function write(buf) {
     return buf;
   if (!ArrayBuffer.isView(buf))
     throw new ERR_INVALID_ARG_TYPE('buf',
-                                   ['Buffer', 'Uint8Array', 'ArrayBufferView'],
+                                   ['Buffer', 'TypedArray', 'DataView'],
                                    buf);
   return decode(this[kNativeDecoder], buf);
 };

test/parallel/test-string-decoder.js

@@ -97,6 +97,17 @@ assert.strictEqual(decoder.lastTotal, 3);
 
 assert.strictEqual(decoder.end(), '\ufffd');
 
+// ArrayBufferView tests
+const arrayBufferViewStr = 'String for ArrayBufferView tests\n';
+const inputBuffer = Buffer.from(arrayBufferViewStr.repeat(8), 'utf8');
+for (const expectView of common.getArrayBufferViews(inputBuffer)) {
+  assert.strictEqual(
+    decoder.write(expectView),
+    inputBuffer.toString('utf8')
+  );
+  assert.strictEqual(decoder.end(), '');
+}
+
 decoder = new StringDecoder('utf8');
 assert.strictEqual(decoder.write(Buffer.from('E18B', 'hex')), '');
 assert.strictEqual(decoder.end(), '\ufffd');
@@ -174,8 +185,8 @@ common.expectsError(
   {
     code: 'ERR_INVALID_ARG_TYPE',
     type: TypeError,
-    message: 'The "buf" argument must be one of type Buffer, Uint8Array, or' +
+    message: 'The "buf" argument must be one of type Buffer, TypedArray,' +
-      ' ArrayBufferView. Received type object'
+      ' or DataView. Received type object'
   }
 );