From ed421855d70c64f55a5cb15a1a46798457697d3e Mon Sep 17 00:00:00 2001
From: Jarred Sumner <709451+Jarred-Sumner@users.noreply.github.com>
Date: Sat, 21 Jan 2023 04:06:06 -0800
Subject: [buffer] Add faster path for Uint8Array

---
 src/bun.js/builtins/cpp/JSBufferConstructorBuiltins.cpp | 8 +++++++-
 src/bun.js/builtins/js/JSBufferConstructor.js           | 6 ++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/bun.js/builtins/cpp/JSBufferConstructorBuiltins.cpp b/src/bun.js/builtins/cpp/JSBufferConstructorBuiltins.cpp
index 213060f58..7025ea8b8 100644
--- a/src/bun.js/builtins/cpp/JSBufferConstructorBuiltins.cpp
+++ b/src/bun.js/builtins/cpp/JSBufferConstructorBuiltins.cpp
@@ -51,7 +51,7 @@ namespace WebCore {
 const JSC::ConstructAbility s_jsBufferConstructorFromCodeConstructAbility = JSC::ConstructAbility::CannotConstruct;
 const JSC::ConstructorKind s_jsBufferConstructorFromCodeConstructorKind = JSC::ConstructorKind::None;
 const JSC::ImplementationVisibility s_jsBufferConstructorFromCodeImplementationVisibility = JSC::ImplementationVisibility::Public;
-const int s_jsBufferConstructorFromCodeLength = 1832;
+const int s_jsBufferConstructorFromCodeLength = 1984;
 static const JSC::Intrinsic s_jsBufferConstructorFromCodeIntrinsic = JSC::NoIntrinsic;
 const char* const s_jsBufferConstructorFromCode =
     "(function (items) {\n" \
@@ -65,6 +65,12 @@ const char* const s_jsBufferConstructorFromCode =
     "      \"The first argument must be one of type string, Buffer, ArrayBuffer, Array, or Array-like Object.\",\n" \
     "    );\n" \
     "\n" \
+    "  if (@argumentCount() === 1 && @isTypedArrayView(items)) {\n" \
+    "    var out = this.allocUnsafe(items.byteLength);\n" \
+    "    out.copy(items);\n" \
+    "    return out;\n" \
+    "  }\n" \
+    "\n" \
     "  //\n" \
     "  if (\n" \
     "    typeof items === \"string\" ||\n" \
diff --git a/src/bun.js/builtins/js/JSBufferConstructor.js b/src/bun.js/builtins/js/JSBufferConstructor.js
index 9f61220cc..4c3650360 100644
--- a/src/bun.js/builtins/js/JSBufferConstructor.js
+++ b/src/bun.js/builtins/js/JSBufferConstructor.js
@@ -36,6 +36,12 @@ function from(items) {
       "The first argument must be one of type string, Buffer, ArrayBuffer, Array, or Array-like Object.",
     );
 
+  if (@argumentCount() === 1 && @isTypedArrayView(items)) {
+    var out = this.allocUnsafe(items.byteLength);
+    out.copy(items);
+    return out;
+  }
+
   // TODO: figure out why private symbol not found
   if (
     typeof items === "string" ||
-- 
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