From d22d2fa6d4d77ff8ea48e5bbfd5496163f509f41 Mon Sep 17 00:00:00 2001
From: Yoo <121166835+ri7116@users.noreply.github.com>
Date: Mon, 11 Aug 2025 12:29:01 +0900
Subject: [PATCH] lib: optimize writable stream buffer clearing

Improved the `clearBuffer` function
by replacing `buffered.splice` with `ArrayPrototypeSlice`.
- Eliminates O(N) shifting overhead.
- Improves CPU utilization and reduces GC overhead.

PR-URL: https://github.com/nodejs/node/pull/59406
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Ethan Arrowood <ethan@arrowood.dev>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
---
 lib/internal/streams/writable.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/internal/streams/writable.js b/lib/internal/streams/writable.js
index a3a1a965b00..84ef2e2629f 100644
--- a/lib/internal/streams/writable.js
+++ b/lib/internal/streams/writable.js
@@ -786,7 +786,7 @@ function clearBuffer(stream, state) {
     if (i === buffered.length) {
       resetBuffer(state);
     } else if (i > 256) {
-      buffered.splice(0, i);
+      state[kBufferedValue] = ArrayPrototypeSlice(buffered, i);
       state.bufferedIndex = 0;
     } else {
       state.bufferedIndex = i;