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stream: never flatten on toArray
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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>
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benjamingr authored and BethGriggs committed Jan 24, 2022
1 parent 46ec74d commit b3390b9
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Showing 3 changed files with 10 additions and 14 deletions.
8 changes: 3 additions & 5 deletions doc/api/stream.md
Original file line number Diff line number Diff line change
Expand Up @@ -1846,12 +1846,10 @@ 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
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4 changes: 0 additions & 4 deletions lib/internal/streams/operators.js
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@@ -1,7 +1,6 @@
'use strict';

const { AbortController } = require('internal/abort_controller');
const { Buffer } = require('buffer');

const {
codes: {
Expand Down Expand Up @@ -224,9 +223,6 @@ async function toArray(options) {
}
ArrayPrototypePush(result, val);
}
if (!this.readableObjectMode) {
return Buffer.concat(result);
}
return result;
}

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12 changes: 7 additions & 5 deletions test/parallel/test-stream-toArray.js
Original file line number Diff line number Diff line change
Expand Up @@ -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());
}

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