stream: never flatten on toArray

PR-URL: #41615 Reviewed-By: Matteo Collina <matteo.collina@gmail.com> Reviewed-By: Robert Nagy <ronagy@icloud.com> Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>

Author: benjamingr

doc/api/stream.md

@@ -1900,12 +1900,10 @@ added: REPLACEME
 * `options` {Object}
  * `signal` {AbortSignal} allows cancelling the toArray operation if the
  signal is aborted.
-* Returns: {Promise} a promise containing an array (if the stream is in
- object mode) or Buffer with the contents of the stream.
+* Returns: {Promise} a promise containing an array with the contents of the
+ stream.
 
-This method allows easily obtaining the contents of a stream. If the
-stream is in [object mode][object-mode] an array of its contents is returned.
-If the stream is not in object mode a Buffer containing its data is returned.
+This method allows easily obtaining the contents of a stream.
 
 As this method reads the entire stream into memory, it negates the benefits of
 streams. It's intended for interoperability and convenience, not as the primary

lib/internal/streams/operators.js

@@ -1,7 +1,6 @@
 'use strict';
 
 const { AbortController } = require('internal/abort_controller');
-const { Buffer } = require('buffer');
 
 const {
  codes: {
@@ -224,9 +223,6 @@ async function toArray(options) {
  }
  ArrayPrototypePush(result, val);
  }
- if (!this.readableObjectMode) {
- return Buffer.concat(result);
- }
  return result;
 }
 

test/parallel/test-stream-toArray.js

@@ -24,14 +24,16 @@ const assert = require('assert');
 }
 
 {
- // Works on a non-object-mode stream and flattens it
+ // Works on a non-object-mode stream
  (async () => {
+ const firstBuffer = Buffer.from([1, 2, 3]);
+ const secondBuffer = Buffer.from([4, 5, 6]);
  const stream = Readable.from(
- [Buffer.from([1, 2, 3]), Buffer.from([4, 5, 6])]
- , { objectMode: false });
+ [firstBuffer, secondBuffer],
+ { objectMode: false });
  const result = await stream.toArray();
- assert.strictEqual(Buffer.isBuffer(result), true);
- assert.deepStrictEqual(Array.from(result), [1, 2, 3, 4, 5, 6]);
+ assert.strictEqual(Array.isArray(result), true);
+ assert.deepStrictEqual(result, [firstBuffer, secondBuffer]);
  })().then(common.mustCall());
 }