From 5a17a5f585ada9ad7a56cae6a2dbd1886476d253 Mon Sep 17 00:00:00 2001
From: overlookmotel <theoverlookmotel@gmail.com>
Date: Mon, 2 Oct 2023 23:18:10 +0100
Subject: [PATCH] Optimize serializing TypedArrays

---
 lib/serialize/buffers.js | 35 ++++++++++-------------------------
 1 file changed, 10 insertions(+), 25 deletions(-)

diff --git a/lib/serialize/buffers.js b/lib/serialize/buffers.js
index 1e70bfa4..6e2d7dcb 100644
--- a/lib/serialize/buffers.js
+++ b/lib/serialize/buffers.js
@@ -3,8 +3,6 @@
  * Serialize buffers
  * ------------------*/
 
-/* eslint-disable no-bitwise */
-
 'use strict';
 
 // Modules
@@ -24,8 +22,6 @@ const bufferToString = Buffer.prototype.toString,
 	typedArrayLengthGetter = Object.getOwnPropertyDescriptor(TypedArrayPrototype, 'byteLength').get,
 	typedArrayOffsetGetter = Object.getOwnPropertyDescriptor(TypedArrayPrototype, 'byteOffset').get;
 
-const bitsRegex = /^(Ui|I)nt(\d+)Array$/;
-
 module.exports = {
 	/**
 	 * Trace Buffer or TypedArray.
@@ -112,32 +108,21 @@ registerSerializer(BUFFER_TYPE, serializeBuffer);
  * @returns {Object} - AST node
  */
 function serializeTypedArray(record) {
-	const {type, bytes, offset, len} = record.extra,
-		match = type.match(bitsRegex),
-		isSigned = match[1] === 'I',
-		bytesPerChar = match[2] / 8,
-		maxByteValue = 256 ** bytesPerChar,
-		signedMaxByteValue = maxByteValue / 2;
-
-	const buf = Buffer.from(bytes).subarray(offset, offset + len);
-
-	const byteNodes = [];
-	for (let pos = 0; pos < buf.length; pos += bytesPerChar) {
-		let byte = 0,
-			byteMultiplier = 1;
-		for (let byteNum = 0; byteNum < bytesPerChar; byteNum++) {
-			byte += buf[pos + byteNum] * byteMultiplier;
-			byteMultiplier <<= 8;
-		}
+	const {extra} = record,
+		ctor = global[extra.type];
 
-		if (isSigned && byte >= signedMaxByteValue) byte -= maxByteValue;
+	// eslint-disable-next-line new-cap
+	const buf = new ctor(extra.bytes, extra.offset, extra.len / ctor.BYTES_PER_ELEMENT);
 
-		byteNodes.push(t.numericLiteral(byte));
+	const byteNodes = [],
+		len = buf.length;
+	for (let index = 0; index < len; index++) {
+		const val = buf[index];
+		byteNodes.push(val === 0 ? null : t.numericLiteral(val));
 	}
 
 	// `new Uint16Array([...])`
-	const ctor = global[type],
-		node = t.newExpression(this.traceAndSerializeGlobal(ctor), [t.arrayExpression(byteNodes)]);
+	const node = t.newExpression(this.traceAndSerializeGlobal(ctor), [t.arrayExpression(byteNodes)]);
 
 	const ctorPrototypeRecord = this.traceValue(ctor.prototype, null, null);
 	return this.wrapWithProperties(node, record, ctorPrototypeRecord, null);