From eda8d563eaaad4f702c829db9ba2713214f2ca89 Mon Sep 17 00:00:00 2001
From: Andreas Kling <andreas@ladybird.org>
Date: Thu, 3 Apr 2025 12:45:25 +0200
Subject: [PATCH] LibJS: Add fast paths in ToNumeric for booleans, null and
 undefined

These are still in the out-of-line "slow path" for ToNumeric, but
skipping all the coercion machinery can save us a lot of time.
---
 Libraries/LibJS/Runtime/Value.cpp | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/Libraries/LibJS/Runtime/Value.cpp b/Libraries/LibJS/Runtime/Value.cpp
index bdc464ee781..a9e6399a3a1 100644
--- a/Libraries/LibJS/Runtime/Value.cpp
+++ b/Libraries/LibJS/Runtime/Value.cpp
@@ -602,6 +602,17 @@ ThrowCompletionOr<GC::Ref<Object>> Value::to_object(VM& vm) const
 // 7.1.3 ToNumeric ( value ), https://tc39.es/ecma262/#sec-tonumeric
 FLATTEN ThrowCompletionOr<Value> Value::to_numeric_slow_case(VM& vm) const
 {
+    // OPTIMIZATION: Fast paths for some trivial common cases.
+    if (is_boolean()) {
+        return Value(as_bool() ? 1 : 0);
+    }
+    if (is_null()) {
+        return Value(0);
+    }
+    if (is_undefined()) {
+        return js_nan();
+    }
+
     // 1. Let primValue be ? ToPrimitive(value, number).
     auto primitive_value = TRY(to_primitive(vm, Value::PreferredType::Number));