util: improve spliceOne perf

Do less variable allocations and reassignments inside spliceOne
since it's relied on by some performance sensitive code.

PR-URL: https://github.com/nodejs/node/pull/20453
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Tiancheng "Timothy" Gu <timothygu99@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>

1 files changed, 33 insertions, 0 deletions

diff --git a/benchmark/util/splice-one.js b/benchmark/util/splice-one.js
new file mode 100644
index 0000000000..5c2a39f6d7
--- /dev/null
+++ b/benchmark/util/splice-one.js
@@ -0,0 +1,33 @@
+'use strict';
+
+const common = require('../common');
+
+const bench = common.createBenchmark(main, {
+  n: [1e7],
+  pos: ['start', 'middle', 'end'],
+  size: [10, 100, 500],
+}, { flags: ['--expose-internals'] });
+
+function main({ n, pos, size }) {
+  const { spliceOne } = require('internal/util');
+  const arr = new Array(size);
+  arr.fill('');
+  let index;
+  switch (pos) {
+    case 'end':
+      index = size - 1;
+      break;
+    case 'middle':
+      index = Math.floor(size / 2);
+      break;
+    default: // start
+      index = 0;
+  }
+
+  bench.start();
+  for (var i = 0; i < n; i++) {
+    spliceOne(arr, index);
+    arr.push('');
+  }
+  bench.end(n);
+}