diff --git a/packages/react-native/Libraries/Image/RCTImageLoader.mm b/packages/react-native/Libraries/Image/RCTImageLoader.mm
index 75362da2dd43..e7e1260240da 100644
--- a/packages/react-native/Libraries/Image/RCTImageLoader.mm
+++ b/packages/react-native/Libraries/Image/RCTImageLoader.mm
@@ -32,7 +32,7 @@ static NSInteger RCTImageBytesForImage(UIImage *image)
   return image.images ? image.images.count * singleImageBytes : singleImageBytes;
 }
 
-static auto currentRequestCount = std::atomic<uint64_t>(0);
+static constinit auto currentRequestCount = std::atomic<uint64_t>(0);
 
 static NSError *addResponseHeadersToError(NSError *originalError, NSHTTPURLResponse *response)
 {
diff --git a/packages/react-native/Libraries/Network/RCTNetworkTask.mm b/packages/react-native/Libraries/Network/RCTNetworkTask.mm
index e397936d31ba..99c9e237a989 100644
--- a/packages/react-native/Libraries/Network/RCTNetworkTask.mm
+++ b/packages/react-native/Libraries/Network/RCTNetworkTask.mm
@@ -21,7 +21,7 @@ @implementation RCTNetworkTask {
   RCTNetworkTask *_selfReference;
 }
 
-static auto currentRequestId = std::atomic<NSUInteger>(0);
+static constinit auto currentRequestId = std::atomic<NSUInteger>(0);
 
 - (instancetype)initWithRequest:(NSURLRequest *)request
                         handler:(id<RCTURLRequestHandler>)handler
diff --git a/packages/react-native/React/Base/RCTUtils.mm b/packages/react-native/React/Base/RCTUtils.mm
index 21ddfb6ff1f2..57949ad56f88 100644
--- a/packages/react-native/React/Base/RCTUtils.mm
+++ b/packages/react-native/React/Base/RCTUtils.mm
@@ -386,7 +386,7 @@ UIDeviceOrientation RCTDeviceOrientation(void)
 
 CGSize RCTScreenSize(void)
 {
-  static std::atomic<CGSize> cachedSize;
+  static constinit std::atomic<CGSize> cachedSize;
   __block CGSize size = cachedSize.load(std::memory_order_relaxed);
 
   if (CGSizeEqualToSize(size, CGSizeZero)) {
diff --git a/packages/react-native/React/CoreModules/RCTDevSettings.mm b/packages/react-native/React/CoreModules/RCTDevSettings.mm
index 89a7b0c793e6..0c8eb0cc091c 100644
--- a/packages/react-native/React/CoreModules/RCTDevSettings.mm
+++ b/packages/react-native/React/CoreModules/RCTDevSettings.mm
@@ -127,7 +127,7 @@ - (void)_reloadWithDefaults:(NSDictionary *)defaultValues
 #if RCT_DEV_SETTINGS_ENABLE_PACKAGER_CONNECTION
 static RCTHandlerToken reloadToken;
 static RCTHandlerToken devMenuToken;
-static std::atomic<int> numInitializedModules{0};
+static constinit std::atomic<int> numInitializedModules{0};
 #endif
 
 @interface RCTDevSettings () <RCTBridgeModule, RCTInvalidating, NativeDevSettingsSpec, RCTDevSettingsInspectable> {
diff --git a/packages/react-native/ReactAndroid/src/main/jni/first-party/fbgloginit/glog_init.cpp b/packages/react-native/ReactAndroid/src/main/jni/first-party/fbgloginit/glog_init.cpp
index c7174b832275..34df76e08dc9 100644
--- a/packages/react-native/ReactAndroid/src/main/jni/first-party/fbgloginit/glog_init.cpp
+++ b/packages/react-native/ReactAndroid/src/main/jni/first-party/fbgloginit/glog_init.cpp
@@ -112,7 +112,7 @@ lastResort(const char* tag, const char* msg, const char* arg = nullptr) {
 namespace facebook::gloginit {
 
 void initialize(const char* tag) {
-  static std::once_flag flag{};
+  static constinit std::once_flag flag{};
   static auto failed = false;
 
   std::call_once(flag, [tag] {
diff --git a/packages/react-native/ReactAndroid/src/main/jni/react/fabric/AnimatedPropBufferEncoder.cpp b/packages/react-native/ReactAndroid/src/main/jni/react/fabric/AnimatedPropBufferEncoder.cpp
index 6331bfe710f1..d8b930215289 100644
--- a/packages/react-native/ReactAndroid/src/main/jni/react/fabric/AnimatedPropBufferEncoder.cpp
+++ b/packages/react-native/ReactAndroid/src/main/jni/react/fabric/AnimatedPropBufferEncoder.cpp
@@ -9,10 +9,13 @@
 
 #include <folly/Conv.h>
 #include <react/renderer/animationbackend/AnimatedPropsSerializer.h>
+#include <array>
 #include <numbers>
 #include <optional>
+#include <span>
 #include <string_view>
 #include <unordered_map>
+#include <utility>
 
 namespace facebook::react {
 
@@ -87,74 +90,110 @@ constexpr int CMD_TRANSFORM_PERSPECTIVE = 112;
 constexpr int CMD_UNIT_PX = 202;
 constexpr int CMD_UNIT_PERCENT = 203;
 
+using CommandEntry = std::pair<std::string_view, int>;
+
+// Group by name length so lookup only scans a small set of candidates.
+template <size_t MaxLength>
+constexpr auto indexCommandLengths(std::span<const CommandEntry> entries) {
+  std::array<std::span<const CommandEntry>, MaxLength + 1> index{};
+  size_t start = 0;
+  for (size_t length = 0; length < index.size(); ++length) {
+    auto end = start;
+    while (end < entries.size() && entries[end].first.size() == length) {
+      ++end;
+    }
+    index[length] = entries.subspan(start, end - start);
+    start = end;
+  }
+  return index;
+}
+
+std::optional<int> findCommand(
+    std::string_view name,
+    std::span<const std::span<const CommandEntry>> index) {
+  if (name.size() >= index.size()) {
+    return std::nullopt;
+  }
+  for (const auto& [key, command] : index[name.size()]) {
+    if (key == name) {
+      return command;
+    }
+  }
+  return std::nullopt;
+}
+
 std::optional<int> propNameToCommand(const std::string& name) {
-  static const std::unordered_map<std::string_view, int> kMap = {
+  static constexpr std::array<CommandEntry, 37> kMap{{
+      {"color", CMD_COLOR},
+      {"zIndex", CMD_Z_INDEX},
       {"opacity", CMD_OPACITY},
       {"elevation", CMD_ELEVATION},
-      {"zIndex", CMD_Z_INDEX},
-      {"shadowOpacity", CMD_SHADOW_OPACITY},
-      {"shadowRadius", CMD_SHADOW_RADIUS},
-      {"backgroundColor", CMD_BACKGROUND_COLOR},
-      {"color", CMD_COLOR},
       {"tintColor", CMD_TINT_COLOR},
-      {"placeholderTextColor", CMD_PLACEHOLDER_TEXT_COLOR},
+      {"transform", CMD_START_OF_TRANSFORM},
+      {"borderColor", CMD_BORDER_COLOR},
       {"shadowColor", CMD_SHADOW_COLOR},
       {"borderRadius", CMD_BORDER_RADIUS},
+      {"outlineColor", CMD_OUTLINE_COLOR},
+      {"outlineWidth", CMD_OUTLINE_WIDTH},
+      {"shadowRadius", CMD_SHADOW_RADIUS},
+      {"outlineOffset", CMD_OUTLINE_OFFSET},
+      {"shadowOpacity", CMD_SHADOW_OPACITY},
+      {"borderEndColor", CMD_BORDER_END_COLOR},
+      {"borderTopColor", CMD_BORDER_TOP_COLOR},
+      {"backgroundColor", CMD_BACKGROUND_COLOR},
+      {"borderLeftColor", CMD_BORDER_LEFT_COLOR},
+      {"borderBlockColor", CMD_BORDER_BLOCK_COLOR},
+      {"borderRightColor", CMD_BORDER_RIGHT_COLOR},
+      {"borderStartColor", CMD_BORDER_START_COLOR},
+      {"borderBottomColor", CMD_BORDER_BOTTOM_COLOR},
+      {"borderEndEndRadius", CMD_BORDER_END_END_RADIUS},
+      {"borderTopEndRadius", CMD_BORDER_TOP_END_RADIUS},
+      {"borderBlockEndColor", CMD_BORDER_BLOCK_END_COLOR},
       {"borderTopLeftRadius", CMD_BORDER_TOP_LEFT_RADIUS},
+      {"borderEndStartRadius", CMD_BORDER_END_START_RADIUS},
+      {"borderStartEndRadius", CMD_BORDER_START_END_RADIUS},
       {"borderTopRightRadius", CMD_BORDER_TOP_RIGHT_RADIUS},
       {"borderTopStartRadius", CMD_BORDER_TOP_START_RADIUS},
-      {"borderTopEndRadius", CMD_BORDER_TOP_END_RADIUS},
+      {"placeholderTextColor", CMD_PLACEHOLDER_TEXT_COLOR},
+      {"borderBlockStartColor", CMD_BORDER_BLOCK_START_COLOR},
+      {"borderBottomEndRadius", CMD_BORDER_BOTTOM_END_RADIUS},
       {"borderBottomLeftRadius", CMD_BORDER_BOTTOM_LEFT_RADIUS},
+      {"borderStartStartRadius", CMD_BORDER_START_START_RADIUS},
       {"borderBottomRightRadius", CMD_BORDER_BOTTOM_RIGHT_RADIUS},
       {"borderBottomStartRadius", CMD_BORDER_BOTTOM_START_RADIUS},
-      {"borderBottomEndRadius", CMD_BORDER_BOTTOM_END_RADIUS},
-      {"borderStartStartRadius", CMD_BORDER_START_START_RADIUS},
-      {"borderStartEndRadius", CMD_BORDER_START_END_RADIUS},
-      {"borderEndStartRadius", CMD_BORDER_END_START_RADIUS},
-      {"borderEndEndRadius", CMD_BORDER_END_END_RADIUS},
-      {"borderColor", CMD_BORDER_COLOR},
-      {"borderTopColor", CMD_BORDER_TOP_COLOR},
-      {"borderBottomColor", CMD_BORDER_BOTTOM_COLOR},
-      {"borderLeftColor", CMD_BORDER_LEFT_COLOR},
-      {"borderRightColor", CMD_BORDER_RIGHT_COLOR},
-      {"borderStartColor", CMD_BORDER_START_COLOR},
-      {"borderEndColor", CMD_BORDER_END_COLOR},
-      {"borderBlockColor", CMD_BORDER_BLOCK_COLOR},
-      {"borderBlockStartColor", CMD_BORDER_BLOCK_START_COLOR},
-      {"borderBlockEndColor", CMD_BORDER_BLOCK_END_COLOR},
-      {"outlineColor", CMD_OUTLINE_COLOR},
-      {"outlineOffset", CMD_OUTLINE_OFFSET},
-      {"outlineWidth", CMD_OUTLINE_WIDTH},
-      {"transform", CMD_START_OF_TRANSFORM},
-  };
-  auto it = kMap.find(name);
-  if (it == kMap.end()) {
-    return std::nullopt;
-  }
-  return it->second;
+  }};
+  static constexpr auto kIndex =
+      indexCommandLengths<kMap.back().first.size()>(kMap);
+  static_assert(
+      kIndex.back().data() ==
+          std::span<const CommandEntry>{kMap}.last(kIndex.back().size()).data(),
+      "Command entries must be sorted by name length");
+  return findCommand(name, kIndex);
 }
 
 std::optional<int> transformNameToCommand(const std::string& name) {
-  static const std::unordered_map<std::string_view, int> kMap = {
-      {"translateX", CMD_TRANSFORM_TRANSLATE_X},
-      {"translateY", CMD_TRANSFORM_TRANSLATE_Y},
+  static constexpr std::array<CommandEntry, 13> kMap{{
       {"scale", CMD_TRANSFORM_SCALE},
+      {"skewX", CMD_TRANSFORM_SKEW_X},
+      {"skewY", CMD_TRANSFORM_SKEW_Y},
+      {"matrix", CMD_TRANSFORM_MATRIX},
+      {"rotate", CMD_TRANSFORM_ROTATE},
       {"scaleX", CMD_TRANSFORM_SCALE_X},
       {"scaleY", CMD_TRANSFORM_SCALE_Y},
-      {"rotate", CMD_TRANSFORM_ROTATE},
       {"rotateX", CMD_TRANSFORM_ROTATE_X},
       {"rotateY", CMD_TRANSFORM_ROTATE_Y},
       {"rotateZ", CMD_TRANSFORM_ROTATE_Z},
-      {"skewX", CMD_TRANSFORM_SKEW_X},
-      {"skewY", CMD_TRANSFORM_SKEW_Y},
-      {"matrix", CMD_TRANSFORM_MATRIX},
+      {"translateX", CMD_TRANSFORM_TRANSLATE_X},
+      {"translateY", CMD_TRANSFORM_TRANSLATE_Y},
       {"perspective", CMD_TRANSFORM_PERSPECTIVE},
-  };
-  auto it = kMap.find(name);
-  if (it == kMap.end()) {
-    return std::nullopt;
-  }
-  return it->second;
+  }};
+  static constexpr auto kIndex =
+      indexCommandLengths<kMap.back().first.size()>(kMap);
+  static_assert(
+      kIndex.back().data() ==
+          std::span<const CommandEntry>{kMap}.last(kIndex.back().size()).data(),
+      "Command entries must be sorted by name length");
+  return findCommand(name, kIndex);
 }
 
 bool packLength(
diff --git a/packages/react-native/ReactAndroid/src/main/jni/react/fabric/FabricMountingManager.cpp b/packages/react-native/ReactAndroid/src/main/jni/react/fabric/FabricMountingManager.cpp
index 8d37b2ba8b01..b5f1eb569b2e 100644
--- a/packages/react-native/ReactAndroid/src/main/jni/react/fabric/FabricMountingManager.cpp
+++ b/packages/react-native/ReactAndroid/src/main/jni/react/fabric/FabricMountingManager.cpp
@@ -28,8 +28,10 @@
 #include <glog/logging.h>
 
 #include <algorithm>
+#include <array>
 #include <cfenv>
 #include <cmath>
+#include <string_view>
 #include <vector>
 
 namespace facebook::react {
@@ -81,7 +83,7 @@ namespace {
 // List of layout-only props extracted from ViewProps.kt used to filter out
 // component props from Props 1.5 to validate the Props 2.0 output
 inline bool isLayoutOnlyProp(const std::string& propName) {
-  static const std::vector<std::string> layoutOnlyProps = {
+  static constexpr std::array<std::string_view, 46> layoutOnlyProps = {
       // Flexbox Alignment
       "alignItems",
       "alignSelf",
@@ -146,8 +148,10 @@ inline bool isLayoutOnlyProp(const std::string& propName) {
       // Other
       "collapsable",
   };
-  return std::find(layoutOnlyProps.begin(), layoutOnlyProps.end(), propName) !=
-      layoutOnlyProps.end();
+  return std::find(
+             layoutOnlyProps.begin(),
+             layoutOnlyProps.end(),
+             std::string_view{propName}) != layoutOnlyProps.end();
 }
 #endif
 
diff --git a/packages/react-native/ReactAndroid/src/main/jni/react/fabric/test/AnimatedPropBufferEncoderTest.cpp b/packages/react-native/ReactAndroid/src/main/jni/react/fabric/test/AnimatedPropBufferEncoderTest.cpp
index 66b2af196ad1..0e9987bf6d18 100644
--- a/packages/react-native/ReactAndroid/src/main/jni/react/fabric/test/AnimatedPropBufferEncoderTest.cpp
+++ b/packages/react-native/ReactAndroid/src/main/jni/react/fabric/test/AnimatedPropBufferEncoderTest.cpp
@@ -9,9 +9,14 @@
 #include <hermes/hermes.h>
 #include <react/fabric/AnimatedPropBufferEncoder.h>
 #include <react/renderer/animationbackend/AnimatedPropsBuilder.h>
+#include <algorithm>
+#include <array>
 #include <cmath>
 #include <limits>
 #include <numbers>
+#include <string>
+#include <string_view>
+#include <utility>
 
 namespace facebook::react {
 
@@ -29,6 +34,8 @@ enum Command : int {
   CMD_PLACEHOLDER_TEXT_COLOR = 18,
   CMD_SHADOW_COLOR = 19,
   CMD_BORDER_RADIUS = 20,
+  CMD_BORDER_END_END_RADIUS = 32,
+  CMD_BORDER_COLOR = 40,
   CMD_BORDER_BLOCK_COLOR = 47,
   CMD_BORDER_BLOCK_START_COLOR = 48,
   CMD_BORDER_BLOCK_END_COLOR = 49,
@@ -36,12 +43,85 @@ enum Command : int {
   CMD_OUTLINE_OFFSET = 51,
   CMD_OUTLINE_WIDTH = 52,
   CMD_TRANSFORM_TRANSLATE_X = 100,
+  CMD_TRANSFORM_TRANSLATE_Y = 101,
   CMD_TRANSFORM_ROTATE = 105,
   CMD_TRANSFORM_SKEW_Y = 110,
+  CMD_TRANSFORM_MATRIX = 111,
   CMD_UNIT_PX = 202,
   CMD_UNIT_PERCENT = 203,
 };
 
+constexpr std::array<std::pair<const char*, int>, 37> kPropCommands{{
+    {"opacity", 10},
+    {"elevation", 11},
+    {"zIndex", 12},
+    {"shadowOpacity", 13},
+    {"shadowRadius", 14},
+    {"backgroundColor", 15},
+    {"color", 16},
+    {"tintColor", 17},
+    {"placeholderTextColor", 18},
+    {"shadowColor", 19},
+    {"borderRadius", 20},
+    {"borderTopLeftRadius", 21},
+    {"borderTopRightRadius", 22},
+    {"borderTopStartRadius", 23},
+    {"borderTopEndRadius", 24},
+    {"borderBottomLeftRadius", 25},
+    {"borderBottomRightRadius", 26},
+    {"borderBottomStartRadius", 27},
+    {"borderBottomEndRadius", 28},
+    {"borderStartStartRadius", 29},
+    {"borderStartEndRadius", 30},
+    {"borderEndStartRadius", 31},
+    {"borderEndEndRadius", 32},
+    {"borderColor", 40},
+    {"borderTopColor", 41},
+    {"borderBottomColor", 42},
+    {"borderLeftColor", 43},
+    {"borderRightColor", 44},
+    {"borderStartColor", 45},
+    {"borderEndColor", 46},
+    {"borderBlockColor", 47},
+    {"borderBlockStartColor", 48},
+    {"borderBlockEndColor", 49},
+    {"outlineColor", 50},
+    {"outlineOffset", 51},
+    {"outlineWidth", 52},
+    {"transform", 2},
+}};
+
+constexpr std::array<std::pair<const char*, int>, 13> kTransformCommands{{
+    {"translateX", 100},
+    {"translateY", 101},
+    {"scale", 102},
+    {"scaleX", 103},
+    {"scaleY", 104},
+    {"rotate", 105},
+    {"rotateX", 106},
+    {"rotateY", 107},
+    {"rotateZ", 108},
+    {"skewX", 109},
+    {"skewY", 110},
+    {"matrix", 111},
+    {"perspective", 112},
+}};
+
+std::array<std::string, 7> lookupBoundaryNames(std::string_view name) {
+  auto differentCase = std::string{name};
+  differentCase[0] = static_cast<char>(differentCase[0] - 'a' + 'A');
+  return {
+      "",
+      std::string{name.substr(0, name.size() - 1)},
+      std::string{name} + "Suffix",
+      differentCase,
+      std::string{name} + '\0',
+      std::string(1, '\0') + std::string{name},
+      std::string{name.substr(0, name.size() / 2)} + '\0' +
+          std::string{name.substr(name.size() / 2)},
+  };
+}
+
 } // namespace
 
 TEST(
@@ -137,6 +217,115 @@ AnimatedPropsBuffer encodeRawProps(const folly::dynamic& props) {
 }
 } // namespace
 
+TEST(AnimatedPropBufferEncoderTest, encodesEveryPropertyCommand) {
+  for (const auto& [name, command] : kPropCommands) {
+    SCOPED_TRACE(name);
+    folly::dynamic value = 1.25;
+    std::vector<int> expectedInts{CMD_START_OF_VIEW, 10, command};
+    std::vector<double> expectedDoubles;
+    if (command == CMD_START_OF_TRANSFORM) {
+      value = folly::dynamic::array;
+      expectedInts.push_back(CMD_END_OF_TRANSFORM);
+    } else if (
+        (command >= CMD_BACKGROUND_COLOR && command <= CMD_SHADOW_COLOR) ||
+        (command >= CMD_BORDER_COLOR && command <= CMD_OUTLINE_COLOR)) {
+      value = int64_t{0xff112233};
+      expectedInts.push_back(static_cast<int32_t>(0xff112233));
+    } else {
+      if (command >= CMD_BORDER_RADIUS &&
+          command <= CMD_BORDER_END_END_RADIUS) {
+        expectedInts.push_back(CMD_UNIT_PX);
+      }
+      expectedDoubles.push_back(1.25);
+    }
+    expectedInts.push_back(CMD_END_OF_VIEW);
+    auto buffer = encodeRawProps(folly::dynamic::object(name, value));
+    EXPECT_EQ(buffer.ints, expectedInts);
+    EXPECT_EQ(buffer.doubles, expectedDoubles);
+    EXPECT_TRUE(buffer.rawProps.empty());
+  }
+}
+
+TEST(AnimatedPropBufferEncoderTest, encodesEveryTransformCommand) {
+  for (const auto& [name, command] : kTransformCommands) {
+    SCOPED_TRACE(name);
+    folly::dynamic value = 1.25;
+    std::vector<double> expectedDoubles{1.25};
+    if (command == CMD_TRANSFORM_MATRIX) {
+      value = folly::dynamic::array;
+      for (int i = 0; i < 16; ++i) {
+        value.push_back(1.25);
+      }
+      expectedDoubles.assign(16, 1.25);
+    }
+    std::vector<int> expectedInts{
+        CMD_START_OF_VIEW, 10, CMD_START_OF_TRANSFORM, command};
+    if (command == CMD_TRANSFORM_TRANSLATE_X ||
+        command == CMD_TRANSFORM_TRANSLATE_Y) {
+      expectedInts.push_back(CMD_UNIT_PX);
+    }
+    expectedInts.push_back(CMD_END_OF_TRANSFORM);
+    expectedInts.push_back(CMD_END_OF_VIEW);
+    auto buffer = encodeRawProps(
+        folly::dynamic::object(
+            "transform",
+            folly::dynamic::array(folly::dynamic::object(name, value))));
+    EXPECT_EQ(buffer.ints, expectedInts);
+    EXPECT_EQ(buffer.doubles, expectedDoubles);
+    EXPECT_TRUE(buffer.rawProps.empty());
+  }
+}
+
+TEST(AnimatedPropBufferEncoderTest, preservesPropertyLookupBoundaryFallbacks) {
+  for (const auto& mapping : kPropCommands) {
+    for (const auto& name : lookupBoundaryNames(mapping.first)) {
+      if (std::any_of(
+              kPropCommands.begin(),
+              kPropCommands.end(),
+              [&](const auto& entry) { return name == entry.first; })) {
+        continue;
+      }
+      SCOPED_TRACE(name);
+      folly::dynamic props = folly::dynamic::object("opacity", 0.5)(name, 1);
+      auto buffer = encodeRawProps(props);
+      EXPECT_EQ(
+          buffer.ints,
+          (std::vector<int>{
+              CMD_START_OF_VIEW, 10, CMD_RAW_PROPS, CMD_END_OF_VIEW}));
+      EXPECT_TRUE(buffer.doubles.empty());
+      ASSERT_EQ(buffer.rawProps.size(), 1);
+      EXPECT_EQ(buffer.rawProps[0], props);
+    }
+  }
+}
+
+TEST(AnimatedPropBufferEncoderTest, preservesTransformLookupBoundaryFallbacks) {
+  for (const auto& mapping : kTransformCommands) {
+    for (const auto& name : lookupBoundaryNames(mapping.first)) {
+      if (std::any_of(
+              kTransformCommands.begin(),
+              kTransformCommands.end(),
+              [&](const auto& entry) { return name == entry.first; })) {
+        continue;
+      }
+      SCOPED_TRACE(name);
+      folly::dynamic props = folly::dynamic::object("opacity", 0.5)(
+          "transform",
+          folly::dynamic::array(
+              folly::dynamic::object("scale", 2),
+              folly::dynamic::object(name, 1)));
+      auto buffer = encodeRawProps(props);
+      EXPECT_EQ(
+          buffer.ints,
+          (std::vector<int>{
+              CMD_START_OF_VIEW, 10, CMD_RAW_PROPS, CMD_END_OF_VIEW}));
+      EXPECT_TRUE(buffer.doubles.empty());
+      ASSERT_EQ(buffer.rawProps.size(), 1);
+      EXPECT_EQ(buffer.rawProps[0], props);
+    }
+  }
+}
+
 TEST(AnimatedPropBufferEncoderTest, encodesIntegerRadiusAndTranslation) {
   auto radius = encodeRawProps(folly::dynamic::object("borderRadius", 4));
   EXPECT_EQ(
diff --git a/packages/react-native/ReactAndroid/src/main/jni/react/hermes/reactexecutor/OnLoad.cpp b/packages/react-native/ReactAndroid/src/main/jni/react/hermes/reactexecutor/OnLoad.cpp
index 53d76082651d..fb890992dd87 100644
--- a/packages/react-native/ReactAndroid/src/main/jni/react/hermes/reactexecutor/OnLoad.cpp
+++ b/packages/react-native/ReactAndroid/src/main/jni/react/hermes/reactexecutor/OnLoad.cpp
@@ -25,7 +25,7 @@ static void hermesFatalHandler(const std::string& reason) {
   __android_log_assert(nullptr, "Hermes", "%s", reason.c_str());
 }
 
-static std::once_flag flag;
+static constinit std::once_flag flag;
 
 static ::hermes::vm::RuntimeConfig makeRuntimeConfig(jlong heapSizeMB) {
   namespace vm = ::hermes::vm;
diff --git a/packages/react-native/ReactAndroid/src/main/jni/react/jni/JReactMarker.cpp b/packages/react-native/ReactAndroid/src/main/jni/react/jni/JReactMarker.cpp
index 0b3e7442a04f..ee710f0d0c8c 100644
--- a/packages/react-native/ReactAndroid/src/main/jni/react/jni/JReactMarker.cpp
+++ b/packages/react-native/ReactAndroid/src/main/jni/react/jni/JReactMarker.cpp
@@ -18,7 +18,7 @@ const int kInstanceKey = 1;
 }
 
 void JReactMarker::setLogPerfMarkerIfNeeded() {
-  static std::once_flag flag{};
+  static constinit std::once_flag flag{};
   std::call_once(flag, []() {
     ReactMarker::logTaggedMarkerImpl = JReactMarker::logPerfMarker;
   });
diff --git a/packages/react-native/ReactAndroid/src/main/jni/react/jni/SafeReleaseJniRef.cpp b/packages/react-native/ReactAndroid/src/main/jni/react/jni/SafeReleaseJniRef.cpp
index 7eb5f504d77c..f8f571570e23 100644
--- a/packages/react-native/ReactAndroid/src/main/jni/react/jni/SafeReleaseJniRef.cpp
+++ b/packages/react-native/ReactAndroid/src/main/jni/react/jni/SafeReleaseJniRef.cpp
@@ -20,7 +20,7 @@ void ensureThreadDurationJNIEnvAttached() {
   // > exits, and call DetachCurrentThread() from there.
   // https://github.com/facebookincubator/fbjni/blob/7b7efda0d49b956acf1d3307510e3c73fc55b404/cxx/fbjni/detail/Environment.h#L101
   // https://developer.android.com/training/articles/perf-jni#threads
-  static thread_local std::optional<jni::ThreadScope> threadScope;
+  static constinit thread_local std::optional<jni::ThreadScope> threadScope;
 
   if (jni::detail::currentOrNull() == nullptr) {
     threadScope.emplace();
diff --git a/packages/react-native/ReactCommon/cxxreact/TraceSection.h b/packages/react-native/ReactCommon/cxxreact/TraceSection.h
index 2c9ff9ddb5f4..7f956ac699c2 100644
--- a/packages/react-native/ReactCommon/cxxreact/TraceSection.h
+++ b/packages/react-native/ReactCommon/cxxreact/TraceSection.h
@@ -168,7 +168,7 @@ inline os_log_t instrumentsLogHandle = nullptr;
 
 static inline os_log_t getOrCreateInstrumentsLogHandle()
 {
-  static std::once_flag flag{};
+  static constinit std::once_flag flag{};
   std::call_once(flag, []() {
     if (!instrumentsLogHandle) {
       instrumentsLogHandle = os_log_create("dev.reactnative.instruments", OS_LOG_CATEGORY_DYNAMIC_TRACING);
diff --git a/packages/react-native/ReactCommon/react/featureflags/ReactNativeFeatureFlags.cpp b/packages/react-native/ReactCommon/react/featureflags/ReactNativeFeatureFlags.cpp
index 4b24a9161d64..ac8ddb96a112 100644
--- a/packages/react-native/ReactCommon/react/featureflags/ReactNativeFeatureFlags.cpp
+++ b/packages/react-native/ReactCommon/react/featureflags/ReactNativeFeatureFlags.cpp
@@ -4,7 +4,7 @@
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  *
- * @generated SignedSource<<e54d2f7c5761d2bdb0edff1065896eb2>>
+ * @generated SignedSource<<56e127471f63e47798ec619e6fa56738>>
  */
 
 /**
@@ -23,7 +23,7 @@ namespace facebook::react {
 
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wglobal-constructors"
-std::unique_ptr<ReactNativeFeatureFlagsAccessor> accessor_;
+constinit std::unique_ptr<ReactNativeFeatureFlagsAccessor> accessor_;
 #pragma GCC diagnostic pop
 
 bool ReactNativeFeatureFlags::commonTestFlag() {
diff --git a/packages/react-native/ReactCommon/react/nativemodule/core/platform/ios/ReactCommon/RCTTurboModuleManager.mm b/packages/react-native/ReactCommon/react/nativemodule/core/platform/ios/ReactCommon/RCTTurboModuleManager.mm
index 83cfe2308b63..7006bf65e226 100644
--- a/packages/react-native/ReactCommon/react/nativemodule/core/platform/ios/ReactCommon/RCTTurboModuleManager.mm
+++ b/packages/react-native/ReactCommon/react/nativemodule/core/platform/ios/ReactCommon/RCTTurboModuleManager.mm
@@ -42,7 +42,7 @@
 namespace {
 int32_t getUniqueId()
 {
-  static std::atomic<int32_t> counter{0};
+  static constinit std::atomic<int32_t> counter{0};
   return counter++;
 }
 
diff --git a/packages/react-native/ReactCommon/react/renderer/animated/NativeAnimatedNodesManager.cpp b/packages/react-native/ReactCommon/react/renderer/animated/NativeAnimatedNodesManager.cpp
index b21524aed354..5c4d70b1ef5f 100644
--- a/packages/react-native/ReactCommon/react/renderer/animated/NativeAnimatedNodesManager.cpp
+++ b/packages/react-native/ReactCommon/react/renderer/animated/NativeAnimatedNodesManager.cpp
@@ -39,7 +39,7 @@ namespace facebook::react {
 
 // Global function pointer for getting current time. Current time
 // can be injected for testing purposes.
-static TimePointFunction g_now = &std::chrono::steady_clock::now;
+static constinit TimePointFunction g_now = &std::chrono::steady_clock::now;
 void g_setNativeAnimatedNowTimestampFunction(TimePointFunction nowFunction) {
   g_now = nowFunction;
 }
@@ -91,7 +91,8 @@ void mergeObjects(folly::dynamic& out, const folly::dynamic& objectToMerge) {
 
 } // namespace
 
-thread_local bool NativeAnimatedNodesManager::isOnRenderThread_{false};
+constinit thread_local bool NativeAnimatedNodesManager::isOnRenderThread_{
+    false};
 
 NativeAnimatedNodesManager::NativeAnimatedNodesManager(
     DirectManipulationCallback&& directManipulationCallback,
diff --git a/packages/react-native/ReactCommon/react/renderer/animated/NativeAnimatedNodesManager.h b/packages/react-native/ReactCommon/react/renderer/animated/NativeAnimatedNodesManager.h
index fc42b1c11a3f..ff630b31209f 100644
--- a/packages/react-native/ReactCommon/react/renderer/animated/NativeAnimatedNodesManager.h
+++ b/packages/react-native/ReactCommon/react/renderer/animated/NativeAnimatedNodesManager.h
@@ -236,7 +236,7 @@ class NativeAnimatedNodesManager : public std::enable_shared_from_this<NativeAni
 
   std::unique_ptr<AnimatedNode> animatedNode(Tag tag, const folly::dynamic &config) noexcept;
 
-  static thread_local bool isOnRenderThread_;
+  static constinit thread_local bool isOnRenderThread_;
 
   std::mutex animatedNodesCreatedAsyncMutex_;
   std::unordered_map<Tag, std::unique_ptr<AnimatedNode>> animatedNodesCreatedAsync_;
diff --git a/packages/react-native/ReactCommon/react/renderer/components/text/BaseParagraphProps.cpp b/packages/react-native/ReactCommon/react/renderer/components/text/BaseParagraphProps.cpp
index 6175bf755ea5..a3f401079f59 100644
--- a/packages/react-native/ReactCommon/react/renderer/components/text/BaseParagraphProps.cpp
+++ b/packages/react-native/ReactCommon/react/renderer/components/text/BaseParagraphProps.cpp
@@ -64,7 +64,7 @@ void BaseParagraphProps::setProp(
   // of these fields together, and because there are some collisions between
   // propnames parsed here and outside of ParagraphAttributes.
   // This code is also duplicated in AndroidTextInput.
-  static auto paDefaults = ParagraphAttributes{};
+  static constinit auto paDefaults = ParagraphAttributes{};
   switch (hash) {
     REBUILD_FIELD_SWITCH_CASE(
         paDefaults,
diff --git a/packages/react-native/ReactCommon/react/renderer/components/textinput/BaseTextInputProps.cpp b/packages/react-native/ReactCommon/react/renderer/components/textinput/BaseTextInputProps.cpp
index 5ce5172499bd..c85f11971acc 100644
--- a/packages/react-native/ReactCommon/react/renderer/components/textinput/BaseTextInputProps.cpp
+++ b/packages/react-native/ReactCommon/react/renderer/components/textinput/BaseTextInputProps.cpp
@@ -151,7 +151,7 @@ void BaseTextInputProps::setProp(
   // propnames parsed here and outside of ParagraphAttributes. For example,
   // textBreakStrategy is duplicated.
   // This code is also duplicated in ParagraphProps.
-  static auto paDefaults = ParagraphAttributes{};
+  static constinit auto paDefaults = ParagraphAttributes{};
   switch (hash) {
     REBUILD_FIELD_SWITCH_CASE(
         paDefaults,
diff --git a/packages/react-native/ReactCommon/react/renderer/components/view/YogaLayoutableShadowNode.cpp b/packages/react-native/ReactCommon/react/renderer/components/view/YogaLayoutableShadowNode.cpp
index 8c12efc94e72..2e934259232e 100644
--- a/packages/react-native/ReactCommon/react/renderer/components/view/YogaLayoutableShadowNode.cpp
+++ b/packages/react-native/ReactCommon/react/renderer/components/view/YogaLayoutableShadowNode.cpp
@@ -62,7 +62,7 @@ static int FabricDefaultYogaLog(
   return size_s;
 }
 
-thread_local LayoutContext threadLocalLayoutContext;
+constinit thread_local LayoutContext threadLocalLayoutContext;
 
 YogaLayoutableShadowNode::YogaLayoutableShadowNode(
     const ShadowNodeFragment& fragment,
diff --git a/packages/react-native/ReactCommon/react/renderer/components/view/YogaStylableProps.cpp b/packages/react-native/ReactCommon/react/renderer/components/view/YogaStylableProps.cpp
index 73a20cedd883..2047c5b303b4 100644
--- a/packages/react-native/ReactCommon/react/renderer/components/view/YogaStylableProps.cpp
+++ b/packages/react-native/ReactCommon/react/renderer/components/view/YogaStylableProps.cpp
@@ -118,7 +118,7 @@ void YogaStylableProps::setProp(
     RawPropsPropNameHash hash,
     const char* propName,
     const RawValue& value) {
-  static const auto ygDefaults = yoga::Style{};
+  static constinit const auto ygDefaults = yoga::Style{};
   static const auto defaults = YogaStylableProps{};
 
   Props::setProp(context, hash, propName, value);
diff --git a/packages/react-native/ReactCommon/react/renderer/core/EventEmitter.cpp b/packages/react-native/ReactCommon/react/renderer/core/EventEmitter.cpp
index ee4f386d614d..a65de91bf0c0 100644
--- a/packages/react-native/ReactCommon/react/renderer/core/EventEmitter.cpp
+++ b/packages/react-native/ReactCommon/react/renderer/core/EventEmitter.cpp
@@ -44,9 +44,7 @@ std::mutex& EventEmitter::DispatchMutex() {
 }
 
 ValueFactory EventEmitter::defaultPayloadFactory() {
-  static auto payloadFactory =
-      ValueFactory{[](jsi::Runtime& runtime) { return jsi::Object(runtime); }};
-  return payloadFactory;
+  return [](jsi::Runtime& runtime) { return jsi::Object(runtime); };
 }
 
 EventEmitter::EventEmitter(
diff --git a/packages/react-native/ReactCommon/react/renderer/core/ReactRootViewTagGenerator.cpp b/packages/react-native/ReactCommon/react/renderer/core/ReactRootViewTagGenerator.cpp
index 8ae8d1e3d7ad..90b7e3f804dc 100644
--- a/packages/react-native/ReactCommon/react/renderer/core/ReactRootViewTagGenerator.cpp
+++ b/packages/react-native/ReactCommon/react/renderer/core/ReactRootViewTagGenerator.cpp
@@ -15,7 +15,7 @@ constexpr SurfaceId ROOT_VIEW_TAG_INCREMENT = 10;
 
 SurfaceId getNextRootViewTag() noexcept {
   // Numbering of these tags goes from 11, 21, 31, ..., 100501, ...
-  static std::atomic<SurfaceId> nextRootViewTag = 1;
+  static constinit std::atomic<SurfaceId> nextRootViewTag = 1;
   return nextRootViewTag += ROOT_VIEW_TAG_INCREMENT;
 }
 
diff --git a/packages/react-native/ReactCommon/react/renderer/core/ShadowNode.cpp b/packages/react-native/ReactCommon/react/renderer/core/ShadowNode.cpp
index 5ed77b7b1e81..4ff280cf23ee 100644
--- a/packages/react-native/ReactCommon/react/renderer/core/ShadowNode.cpp
+++ b/packages/react-native/ReactCommon/react/renderer/core/ShadowNode.cpp
@@ -25,7 +25,8 @@ namespace facebook::react {
  * tree simultaneously. This thread_local flag allows enabling the updates for
  * chosen threads.
  */
-thread_local bool useRuntimeShadowNodeReferenceUpdateOnThread{false}; // NOLINT
+constinit thread_local bool useRuntimeShadowNodeReferenceUpdateOnThread{
+    false}; // NOLINT
 
 /* static */ void ShadowNode::setUseRuntimeShadowNodeReferenceUpdateOnThread(
     bool isEnabled) {
diff --git a/packages/react-native/ReactCommon/react/renderer/core/ShadowNodeFragment.cpp b/packages/react-native/ReactCommon/react/renderer/core/ShadowNodeFragment.cpp
index 186de7a87b90..1534c4971b8e 100644
--- a/packages/react-native/ReactCommon/react/renderer/core/ShadowNodeFragment.cpp
+++ b/packages/react-native/ReactCommon/react/renderer/core/ShadowNodeFragment.cpp
@@ -16,20 +16,20 @@ namespace facebook::react {
 #endif
 
 const Props::Shared& ShadowNodeFragment::propsPlaceholder() {
-  NO_DESTROY static Props::Shared instance;
+  NO_DESTROY static constinit Props::Shared instance;
   return instance;
 }
 
 const std::shared_ptr<const std::vector<std::shared_ptr<const ShadowNode>>>&
 ShadowNodeFragment::childrenPlaceholder() {
-  NO_DESTROY static std::shared_ptr<
+  NO_DESTROY static constinit std::shared_ptr<
       const std::vector<std::shared_ptr<const ShadowNode>>>
       instance;
   return instance;
 }
 
 const State::Shared& ShadowNodeFragment::statePlaceholder() {
-  NO_DESTROY static State::Shared instance;
+  NO_DESTROY static constinit State::Shared instance;
   return instance;
 }
 
diff --git a/packages/react-native/ReactCommon/react/renderer/core/tests/EventEmitterTest.cpp b/packages/react-native/ReactCommon/react/renderer/core/tests/EventEmitterTest.cpp
new file mode 100644
index 000000000000..5202b37f19c3
--- /dev/null
+++ b/packages/react-native/ReactCommon/react/renderer/core/tests/EventEmitterTest.cpp
@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include <gtest/gtest.h>
+#include <hermes/hermes.h>
+#include <react/renderer/core/EventEmitter.h>
+
+namespace facebook::react {
+
+TEST(EventEmitterTest, defaultPayloadFactoryCreatesFreshEmptyObjects) {
+  auto runtime = hermes::makeHermesRuntime();
+  auto factory = EventEmitter::defaultPayloadFactory();
+
+  auto first = factory(*runtime).getObject(*runtime);
+  EXPECT_EQ(first.getPropertyNames(*runtime).size(*runtime), 0u);
+  first.setProperty(*runtime, "mutation", 42);
+  EXPECT_EQ(first.getProperty(*runtime, "mutation").getNumber(), 42);
+
+  auto second = factory(*runtime).getObject(*runtime);
+  EXPECT_EQ(second.getPropertyNames(*runtime).size(*runtime), 0u);
+  EXPECT_FALSE(second.hasProperty(*runtime, "mutation"));
+}
+
+TEST(EventEmitterTest, defaultPayloadFactoryUsesSuppliedRuntime) {
+  auto firstRuntime = hermes::makeHermesRuntime();
+  auto secondRuntime = hermes::makeHermesRuntime();
+  auto factory = EventEmitter::defaultPayloadFactory();
+
+  auto first = factory(*firstRuntime).getObject(*firstRuntime);
+  first.setProperty(*firstRuntime, "mutation", 42);
+
+  auto second = factory(*secondRuntime).getObject(*secondRuntime);
+  EXPECT_EQ(second.getPropertyNames(*secondRuntime).size(*secondRuntime), 0u);
+  EXPECT_FALSE(second.hasProperty(*secondRuntime, "mutation"));
+  EXPECT_EQ(first.getProperty(*firstRuntime, "mutation").getNumber(), 42);
+}
+
+} // namespace facebook::react
diff --git a/packages/react-native/ReactCommon/react/renderer/graphics/platform/android/react/renderer/graphics/PlatformColorParser.cpp b/packages/react-native/ReactCommon/react/renderer/graphics/platform/android/react/renderer/graphics/PlatformColorParser.cpp
index 5e82135e65b1..68f962ff320f 100644
--- a/packages/react-native/ReactCommon/react/renderer/graphics/platform/android/react/renderer/graphics/PlatformColorParser.cpp
+++ b/packages/react-native/ReactCommon/react/renderer/graphics/platform/android/react/renderer/graphics/PlatformColorParser.cpp
@@ -69,12 +69,12 @@ SharedColor parsePlatformColor(
     if (!resourcePaths.empty()) {
       // Cache the (costly) JNI results. A cached nullopt is an explicit miss,
       // distinct from a path that resolves to transparent (ARGB 0).
-      static std::mutex getColorCacheMutex;
+      static constinit std::mutex getColorCacheMutex;
       static folly::EvictingCacheMap<size_t, std::optional<Color>>
           getColorCache(64);
 
       // Listen for appearance changes, which should invalidate the cache
-      static std::once_flag setupCacheInvalidation;
+      static constinit std::once_flag setupCacheInvalidation;
       std::call_once(
           setupCacheInvalidation,
           configurePlatformColorCacheInvalidationHook,
diff --git a/packages/react-native/ReactCommon/react/renderer/runtimescheduler/RuntimeScheduler_Legacy.cpp b/packages/react-native/ReactCommon/react/renderer/runtimescheduler/RuntimeScheduler_Legacy.cpp
index 90057c69124b..552ab8104ed3 100644
--- a/packages/react-native/ReactCommon/react/renderer/runtimescheduler/RuntimeScheduler_Legacy.cpp
+++ b/packages/react-native/ReactCommon/react/renderer/runtimescheduler/RuntimeScheduler_Legacy.cpp
@@ -133,7 +133,7 @@ void RuntimeScheduler_Legacy::executeNowOnTheSameThread(
     RawCallback&& callback) {
   TraceSection s("RuntimeScheduler::executeNowOnTheSameThread");
 
-  static thread_local jsi::Runtime* runtimePtr = nullptr;
+  static constinit thread_local jsi::Runtime* runtimePtr = nullptr;
 
   if (runtimePtr == nullptr) {
     runtimeAccessRequests_ += 1;
diff --git a/packages/react-native/ReactCommon/react/renderer/runtimescheduler/RuntimeScheduler_Modern.cpp b/packages/react-native/ReactCommon/react/renderer/runtimescheduler/RuntimeScheduler_Modern.cpp
index 791a4f3a8d0b..2e57e23b0ce2 100644
--- a/packages/react-native/ReactCommon/react/renderer/runtimescheduler/RuntimeScheduler_Modern.cpp
+++ b/packages/react-native/ReactCommon/react/renderer/runtimescheduler/RuntimeScheduler_Modern.cpp
@@ -153,7 +153,7 @@ void RuntimeScheduler_Modern::executeNowOnTheSameThread(
     RawCallback&& callback) {
   TraceSection s("RuntimeScheduler::executeNowOnTheSameThread");
 
-  static thread_local jsi::Runtime* runtimePtr = nullptr;
+  static constinit thread_local jsi::Runtime* runtimePtr = nullptr;
 
   auto currentTime = now_();
   auto priority = SchedulerPriority::ImmediatePriority;
diff --git a/packages/react-native/ReactCommon/react/renderer/runtimescheduler/Task.cpp b/packages/react-native/ReactCommon/react/renderer/runtimescheduler/Task.cpp
index fa44d3d6f812..fced88bb4079 100644
--- a/packages/react-native/ReactCommon/react/renderer/runtimescheduler/Task.cpp
+++ b/packages/react-native/ReactCommon/react/renderer/runtimescheduler/Task.cpp
@@ -13,7 +13,7 @@ namespace facebook::react {
 namespace {
 
 inline uint64_t getNextId() noexcept {
-  static std::atomic<uint64_t> nextId = 1;
+  static constinit std::atomic<uint64_t> nextId = 1;
   return nextId++;
 }
 
diff --git a/packages/react-native/ReactCommon/react/renderer/telemetry/TransactionTelemetry.cpp b/packages/react-native/ReactCommon/react/renderer/telemetry/TransactionTelemetry.cpp
index a5506321e04f..e30402c6f047 100644
--- a/packages/react-native/ReactCommon/react/renderer/telemetry/TransactionTelemetry.cpp
+++ b/packages/react-native/ReactCommon/react/renderer/telemetry/TransactionTelemetry.cpp
@@ -13,7 +13,8 @@
 
 namespace facebook::react {
 
-thread_local TransactionTelemetry* threadLocalTransactionTelemetry = nullptr;
+constinit thread_local TransactionTelemetry* threadLocalTransactionTelemetry =
+    nullptr;
 
 TransactionTelemetry::TransactionTelemetry()
     : TransactionTelemetry(telemetryTimePointNow) {}
diff --git a/packages/react-native/ReactCommon/reactperflogger/reactperflogger/ReactPerfetto.cpp b/packages/react-native/ReactCommon/reactperflogger/reactperflogger/ReactPerfetto.cpp
index 77ebb2845ada..86f7b3375406 100644
--- a/packages/react-native/ReactCommon/reactperflogger/reactperflogger/ReactPerfetto.cpp
+++ b/packages/react-native/ReactCommon/reactperflogger/reactperflogger/ReactPerfetto.cpp
@@ -22,7 +22,7 @@
 
 namespace facebook::react {
 
-std::once_flag perfettoInit;
+constinit std::once_flag perfettoInit;
 void initializePerfetto() {
   std::call_once(perfettoInit, []() {
     perfetto::TracingInitArgs args;
diff --git a/packages/react-native/ReactCommon/runtimeexecutor/platform/ios/ReactCommon/RuntimeExecutorSyncUIThreadUtils.mm b/packages/react-native/ReactCommon/runtimeexecutor/platform/ios/ReactCommon/RuntimeExecutorSyncUIThreadUtils.mm
index 77273fdf9475..3119ee46bd40 100644
--- a/packages/react-native/ReactCommon/runtimeexecutor/platform/ios/ReactCommon/RuntimeExecutorSyncUIThreadUtils.mm
+++ b/packages/react-native/ReactCommon/runtimeexecutor/platform/ios/ReactCommon/RuntimeExecutorSyncUIThreadUtils.mm
@@ -53,7 +53,7 @@ OnScopeExit onScopeExit(^{
 // Protects access to g_uiTask
 std::mutex &g_mutex()
 {
-  static std::mutex mutex;
+  static constinit std::mutex mutex;
   return mutex;
 }
 
@@ -65,13 +65,13 @@ OnScopeExit onScopeExit(^{
 
 std::mutex &g_ticket()
 {
-  static std::mutex ticket;
+  static constinit std::mutex ticket;
   return ticket;
 }
 
 std::optional<UITask> &g_uiTask()
 {
-  static std::optional<UITask> uiTaskQueue;
+  static constinit std::optional<UITask> uiTaskQueue;
   return uiTaskQueue;
 }
 
diff --git a/packages/react-native/ReactCommon/yoga/test/BaselineTest.cpp b/packages/react-native/ReactCommon/yoga/test/BaselineTest.cpp
index 5e5c96ae892f..505ceda62b0f 100644
--- a/packages/react-native/ReactCommon/yoga/test/BaselineTest.cpp
+++ b/packages/react-native/ReactCommon/yoga/test/BaselineTest.cpp
@@ -19,6 +19,20 @@
 namespace facebook::yoga {
 namespace {
 
+TEST(ConfigTest, defaultConfigIsConstexpr) {
+#if defined(_WIN32)
+  const auto& config = Config::getDefault();
+  const auto copy = config;
+#else
+  constexpr const auto& config = Config::getDefault();
+  constexpr auto copy = config;
+  static_assert(&config == &Config::getDefault());
+#endif
+
+  EXPECT_EQ(&config, YGConfigGetDefault());
+  EXPECT_EQ(copy.getPointScaleFactor(), config.getPointScaleFactor());
+}
+
 void setMeasuredSize(Node& node, float width, float height) {
   node.setLayoutMeasuredDimension(width, Dimension::Width);
   node.setLayoutMeasuredDimension(height, Dimension::Height);
diff --git a/packages/react-native/ReactCommon/yoga/yoga/config/Config.cpp b/packages/react-native/ReactCommon/yoga/yoga/config/Config.cpp
index 0f5fb019cb18..c589a9c4e2aa 100644
--- a/packages/react-native/ReactCommon/yoga/yoga/config/Config.cpp
+++ b/packages/react-native/ReactCommon/yoga/yoga/config/Config.cpp
@@ -106,7 +106,8 @@ void Config::log(
     LogLevel logLevel,
     const char* format,
     va_list args) const {
-  logger_(this, node, unscopedEnum(logLevel), format, args);
+  const auto logger = logger_ != nullptr ? logger_ : getDefaultLogger();
+  logger(this, node, unscopedEnum(logLevel), format, args);
 }
 
 void Config::setCloneNodeCallback(YGCloneNodeFunc cloneNode) {
@@ -127,9 +128,11 @@ YGNodeRef Config::cloneNode(
   return clone;
 }
 
+#if defined(_WIN32)
 /*static*/ const Config& Config::getDefault() {
-  static Config config{getDefaultLogger()};
+  static constexpr Config config{nullptr};
   return config;
 }
+#endif
 
 } // namespace facebook::yoga
diff --git a/packages/react-native/ReactCommon/yoga/yoga/config/Config.h b/packages/react-native/ReactCommon/yoga/yoga/config/Config.h
index 90bb578e65a0..95f63e87a483 100644
--- a/packages/react-native/ReactCommon/yoga/yoga/config/Config.h
+++ b/packages/react-native/ReactCommon/yoga/yoga/config/Config.h
@@ -32,7 +32,7 @@ bool configUpdateInvalidatesLayout(
 
 class YG_EXPORT Config : public ::YGConfig {
  public:
-  explicit Config(YGLogger logger) : logger_{logger} {}
+  explicit constexpr Config(YGLogger logger) : logger_{logger} {}
 
   void setUseWebDefaults(bool useWebDefaults);
   bool useWebDefaults() const;
@@ -66,9 +66,20 @@ class YG_EXPORT Config : public ::YGConfig {
   YGNodeRef
   cloneNode(YGNodeConstRef node, YGNodeConstRef owner, size_t childIndex) const;
 
+#if defined(_WIN32)
   static const Config& getDefault();
+#else
+  static constexpr const Config& getDefault() {
+    return defaultConfig_;
+  }
+#endif
 
  private:
+#if !defined(_WIN32)
+  // NOLINTNEXTLINE(facebook-hte-NonPodStaticDeclaration)
+  static constinit const Config defaultConfig_;
+#endif
+
   YGCloneNodeFunc cloneNodeCallback_{nullptr};
   YGLogger logger_{};
 
@@ -82,6 +93,10 @@ class YG_EXPORT Config : public ::YGConfig {
   void* context_ = nullptr;
 };
 
+#if !defined(_WIN32)
+inline constexpr Config Config::defaultConfig_{nullptr};
+#endif
+
 inline Config* resolveRef(const YGConfigRef ref) {
   return static_cast<Config*>(ref);
 }
diff --git a/packages/react-native/ReactCxxPlatform/react/profiling/perfetto.cpp b/packages/react-native/ReactCxxPlatform/react/profiling/perfetto.cpp
index c15a1179ae77..cc448e654ae8 100644
--- a/packages/react-native/ReactCxxPlatform/react/profiling/perfetto.cpp
+++ b/packages/react-native/ReactCxxPlatform/react/profiling/perfetto.cpp
@@ -11,7 +11,7 @@
 #include <mutex>
 
 void initializePerfetto() {
-  static std::once_flag s_PerfettoIsInitialized;
+  static constinit std::once_flag s_PerfettoIsInitialized;
 
   std::call_once(s_PerfettoIsInitialized, []() {
     perfetto::TracingInitArgs args;
diff --git a/packages/react-native/scripts/featureflags/templates/common-cxx/ReactNativeFeatureFlags.cpp-template.js b/packages/react-native/scripts/featureflags/templates/common-cxx/ReactNativeFeatureFlags.cpp-template.js
index 32d4e1788582..6c51a17a5817 100644
--- a/packages/react-native/scripts/featureflags/templates/common-cxx/ReactNativeFeatureFlags.cpp-template.js
+++ b/packages/react-native/scripts/featureflags/templates/common-cxx/ReactNativeFeatureFlags.cpp-template.js
@@ -31,7 +31,7 @@ namespace facebook::react {
 
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wglobal-constructors"
-std::unique_ptr<ReactNativeFeatureFlagsAccessor> accessor_;
+constinit std::unique_ptr<ReactNativeFeatureFlagsAccessor> accessor_;
 #pragma GCC diagnostic pop
 
 ${Object.entries(definitions.common)
diff --git a/scripts/cxx-api/api-snapshots/ReactAndroidDebugCxx.api b/scripts/cxx-api/api-snapshots/ReactAndroidDebugCxx.api
index 6d9ac1caa787..0b8d391a4639 100644
--- a/scripts/cxx-api/api-snapshots/ReactAndroidDebugCxx.api
+++ b/scripts/cxx-api/api-snapshots/ReactAndroidDebugCxx.api
@@ -6560,13 +6560,13 @@ constexpr bool facebook::yoga::operator>=(facebook::yoga::FloatOptional lhs, fac
 constexpr facebook::yoga::FloatOptional facebook::yoga::operator+(facebook::yoga::FloatOptional lhs, facebook::yoga::FloatOptional rhs);
 
 class facebook::yoga::Config : public YGConfig {
-  public Config(YGLogger logger);
   public YGNodeRef cloneNode(YGNodeConstRef node, YGNodeConstRef owner, size_t childIndex) const;
   public bool hasErrata(facebook::yoga::Errata errata) const;
   public bool useWebDefaults() const;
+  public constexpr Config(YGLogger logger);
   public facebook::yoga::Errata getErrata() const;
   public float getPointScaleFactor() const;
-  public static const facebook::yoga::Config& getDefault();
+  public static constexpr const facebook::yoga::Config& getDefault();
   public uint32_t getVersion() const noexcept;
   public void addErrata(facebook::yoga::Errata errata);
   public void log(const facebook::yoga::Node* node, facebook::yoga::LogLevel logLevel, const char* format, va_list args) const;
diff --git a/scripts/cxx-api/api-snapshots/ReactAndroidFrameworksCxx.api b/scripts/cxx-api/api-snapshots/ReactAndroidFrameworksCxx.api
index d2b41ea569c8..063d23740fac 100644
--- a/scripts/cxx-api/api-snapshots/ReactAndroidFrameworksCxx.api
+++ b/scripts/cxx-api/api-snapshots/ReactAndroidFrameworksCxx.api
@@ -11010,13 +11010,13 @@ constexpr bool facebook::yoga::operator>=(facebook::yoga::FloatOptional lhs, fac
 constexpr facebook::yoga::FloatOptional facebook::yoga::operator+(facebook::yoga::FloatOptional lhs, facebook::yoga::FloatOptional rhs);
 
 class facebook::yoga::Config : public YGConfig {
-  public Config(YGLogger logger);
   public YGNodeRef cloneNode(YGNodeConstRef node, YGNodeConstRef owner, size_t childIndex) const;
   public bool hasErrata(facebook::yoga::Errata errata) const;
   public bool useWebDefaults() const;
+  public constexpr Config(YGLogger logger);
   public facebook::yoga::Errata getErrata() const;
   public float getPointScaleFactor() const;
-  public static const facebook::yoga::Config& getDefault();
+  public static constexpr const facebook::yoga::Config& getDefault();
   public uint32_t getVersion() const noexcept;
   public void addErrata(facebook::yoga::Errata errata);
   public void log(const facebook::yoga::Node* node, facebook::yoga::LogLevel logLevel, const char* format, va_list args) const;
diff --git a/scripts/cxx-api/api-snapshots/ReactAndroidNewarchCxx.api b/scripts/cxx-api/api-snapshots/ReactAndroidNewarchCxx.api
index 57f7bc098311..636dea874c76 100644
--- a/scripts/cxx-api/api-snapshots/ReactAndroidNewarchCxx.api
+++ b/scripts/cxx-api/api-snapshots/ReactAndroidNewarchCxx.api
@@ -6409,13 +6409,13 @@ constexpr bool facebook::yoga::operator>=(facebook::yoga::FloatOptional lhs, fac
 constexpr facebook::yoga::FloatOptional facebook::yoga::operator+(facebook::yoga::FloatOptional lhs, facebook::yoga::FloatOptional rhs);
 
 class facebook::yoga::Config : public YGConfig {
-  public Config(YGLogger logger);
   public YGNodeRef cloneNode(YGNodeConstRef node, YGNodeConstRef owner, size_t childIndex) const;
   public bool hasErrata(facebook::yoga::Errata errata) const;
   public bool useWebDefaults() const;
+  public constexpr Config(YGLogger logger);
   public facebook::yoga::Errata getErrata() const;
   public float getPointScaleFactor() const;
-  public static const facebook::yoga::Config& getDefault();
+  public static constexpr const facebook::yoga::Config& getDefault();
   public uint32_t getVersion() const noexcept;
   public void addErrata(facebook::yoga::Errata errata);
   public void log(const facebook::yoga::Node* node, facebook::yoga::LogLevel logLevel, const char* format, va_list args) const;
diff --git a/scripts/cxx-api/api-snapshots/ReactAndroidReleaseCxx.api b/scripts/cxx-api/api-snapshots/ReactAndroidReleaseCxx.api
index 57f7bc098311..636dea874c76 100644
--- a/scripts/cxx-api/api-snapshots/ReactAndroidReleaseCxx.api
+++ b/scripts/cxx-api/api-snapshots/ReactAndroidReleaseCxx.api
@@ -6409,13 +6409,13 @@ constexpr bool facebook::yoga::operator>=(facebook::yoga::FloatOptional lhs, fac
 constexpr facebook::yoga::FloatOptional facebook::yoga::operator+(facebook::yoga::FloatOptional lhs, facebook::yoga::FloatOptional rhs);
 
 class facebook::yoga::Config : public YGConfig {
-  public Config(YGLogger logger);
   public YGNodeRef cloneNode(YGNodeConstRef node, YGNodeConstRef owner, size_t childIndex) const;
   public bool hasErrata(facebook::yoga::Errata errata) const;
   public bool useWebDefaults() const;
+  public constexpr Config(YGLogger logger);
   public facebook::yoga::Errata getErrata() const;
   public float getPointScaleFactor() const;
-  public static const facebook::yoga::Config& getDefault();
+  public static constexpr const facebook::yoga::Config& getDefault();
   public uint32_t getVersion() const noexcept;
   public void addErrata(facebook::yoga::Errata errata);
   public void log(const facebook::yoga::Node* node, facebook::yoga::LogLevel logLevel, const char* format, va_list args) const;
diff --git a/scripts/cxx-api/api-snapshots/ReactAppleDebugCxx.api b/scripts/cxx-api/api-snapshots/ReactAppleDebugCxx.api
index 9815b007ef82..1ca098e4b6f9 100644
--- a/scripts/cxx-api/api-snapshots/ReactAppleDebugCxx.api
+++ b/scripts/cxx-api/api-snapshots/ReactAppleDebugCxx.api
@@ -8313,13 +8313,13 @@ constexpr bool facebook::yoga::operator>=(facebook::yoga::FloatOptional lhs, fac
 constexpr facebook::yoga::FloatOptional facebook::yoga::operator+(facebook::yoga::FloatOptional lhs, facebook::yoga::FloatOptional rhs);
 
 class facebook::yoga::Config : public YGConfig {
-  public Config(YGLogger logger);
   public YGNodeRef cloneNode(YGNodeConstRef node, YGNodeConstRef owner, size_t childIndex) const;
   public bool hasErrata(facebook::yoga::Errata errata) const;
   public bool useWebDefaults() const;
+  public constexpr Config(YGLogger logger);
   public facebook::yoga::Errata getErrata() const;
   public float getPointScaleFactor() const;
-  public static const facebook::yoga::Config& getDefault();
+  public static constexpr const facebook::yoga::Config& getDefault();
   public uint32_t getVersion() const noexcept;
   public void addErrata(facebook::yoga::Errata errata);
   public void log(const facebook::yoga::Node* node, facebook::yoga::LogLevel logLevel, const char* format, va_list args) const;
diff --git a/scripts/cxx-api/api-snapshots/ReactAppleFrameworksCxx.api b/scripts/cxx-api/api-snapshots/ReactAppleFrameworksCxx.api
index 7d95a55afddb..4d74084f2445 100644
--- a/scripts/cxx-api/api-snapshots/ReactAppleFrameworksCxx.api
+++ b/scripts/cxx-api/api-snapshots/ReactAppleFrameworksCxx.api
@@ -12796,13 +12796,13 @@ constexpr bool facebook::yoga::operator>=(facebook::yoga::FloatOptional lhs, fac
 constexpr facebook::yoga::FloatOptional facebook::yoga::operator+(facebook::yoga::FloatOptional lhs, facebook::yoga::FloatOptional rhs);
 
 class facebook::yoga::Config : public YGConfig {
-  public Config(YGLogger logger);
   public YGNodeRef cloneNode(YGNodeConstRef node, YGNodeConstRef owner, size_t childIndex) const;
   public bool hasErrata(facebook::yoga::Errata errata) const;
   public bool useWebDefaults() const;
+  public constexpr Config(YGLogger logger);
   public facebook::yoga::Errata getErrata() const;
   public float getPointScaleFactor() const;
-  public static const facebook::yoga::Config& getDefault();
+  public static constexpr const facebook::yoga::Config& getDefault();
   public uint32_t getVersion() const noexcept;
   public void addErrata(facebook::yoga::Errata errata);
   public void log(const facebook::yoga::Node* node, facebook::yoga::LogLevel logLevel, const char* format, va_list args) const;
diff --git a/scripts/cxx-api/api-snapshots/ReactAppleNewarchCxx.api b/scripts/cxx-api/api-snapshots/ReactAppleNewarchCxx.api
index e74431082e29..df4b2417b5af 100644
--- a/scripts/cxx-api/api-snapshots/ReactAppleNewarchCxx.api
+++ b/scripts/cxx-api/api-snapshots/ReactAppleNewarchCxx.api
@@ -8164,13 +8164,13 @@ constexpr bool facebook::yoga::operator>=(facebook::yoga::FloatOptional lhs, fac
 constexpr facebook::yoga::FloatOptional facebook::yoga::operator+(facebook::yoga::FloatOptional lhs, facebook::yoga::FloatOptional rhs);
 
 class facebook::yoga::Config : public YGConfig {
-  public Config(YGLogger logger);
   public YGNodeRef cloneNode(YGNodeConstRef node, YGNodeConstRef owner, size_t childIndex) const;
   public bool hasErrata(facebook::yoga::Errata errata) const;
   public bool useWebDefaults() const;
+  public constexpr Config(YGLogger logger);
   public facebook::yoga::Errata getErrata() const;
   public float getPointScaleFactor() const;
-  public static const facebook::yoga::Config& getDefault();
+  public static constexpr const facebook::yoga::Config& getDefault();
   public uint32_t getVersion() const noexcept;
   public void addErrata(facebook::yoga::Errata errata);
   public void log(const facebook::yoga::Node* node, facebook::yoga::LogLevel logLevel, const char* format, va_list args) const;
diff --git a/scripts/cxx-api/api-snapshots/ReactAppleReleaseCxx.api b/scripts/cxx-api/api-snapshots/ReactAppleReleaseCxx.api
index 08697b483f6e..1c4998b3d189 100644
--- a/scripts/cxx-api/api-snapshots/ReactAppleReleaseCxx.api
+++ b/scripts/cxx-api/api-snapshots/ReactAppleReleaseCxx.api
@@ -8172,13 +8172,13 @@ constexpr bool facebook::yoga::operator>=(facebook::yoga::FloatOptional lhs, fac
 constexpr facebook::yoga::FloatOptional facebook::yoga::operator+(facebook::yoga::FloatOptional lhs, facebook::yoga::FloatOptional rhs);
 
 class facebook::yoga::Config : public YGConfig {
-  public Config(YGLogger logger);
   public YGNodeRef cloneNode(YGNodeConstRef node, YGNodeConstRef owner, size_t childIndex) const;
   public bool hasErrata(facebook::yoga::Errata errata) const;
   public bool useWebDefaults() const;
+  public constexpr Config(YGLogger logger);
   public facebook::yoga::Errata getErrata() const;
   public float getPointScaleFactor() const;
-  public static const facebook::yoga::Config& getDefault();
+  public static constexpr const facebook::yoga::Config& getDefault();
   public uint32_t getVersion() const noexcept;
   public void addErrata(facebook::yoga::Errata errata);
   public void log(const facebook::yoga::Node* node, facebook::yoga::LogLevel logLevel, const char* format, va_list args) const;
diff --git a/scripts/cxx-api/api-snapshots/ReactCommonDebugCxx.api b/scripts/cxx-api/api-snapshots/ReactCommonDebugCxx.api
index cd608ca12bc3..dfbc4d44eccf 100644
--- a/scripts/cxx-api/api-snapshots/ReactCommonDebugCxx.api
+++ b/scripts/cxx-api/api-snapshots/ReactCommonDebugCxx.api
@@ -3795,13 +3795,13 @@ constexpr bool facebook::yoga::operator>=(facebook::yoga::FloatOptional lhs, fac
 constexpr facebook::yoga::FloatOptional facebook::yoga::operator+(facebook::yoga::FloatOptional lhs, facebook::yoga::FloatOptional rhs);
 
 class facebook::yoga::Config : public YGConfig {
-  public Config(YGLogger logger);
   public YGNodeRef cloneNode(YGNodeConstRef node, YGNodeConstRef owner, size_t childIndex) const;
   public bool hasErrata(facebook::yoga::Errata errata) const;
   public bool useWebDefaults() const;
+  public constexpr Config(YGLogger logger);
   public facebook::yoga::Errata getErrata() const;
   public float getPointScaleFactor() const;
-  public static const facebook::yoga::Config& getDefault();
+  public static constexpr const facebook::yoga::Config& getDefault();
   public uint32_t getVersion() const noexcept;
   public void addErrata(facebook::yoga::Errata errata);
   public void log(const facebook::yoga::Node* node, facebook::yoga::LogLevel logLevel, const char* format, va_list args) const;
diff --git a/scripts/cxx-api/api-snapshots/ReactCommonFrameworksCxx.api b/scripts/cxx-api/api-snapshots/ReactCommonFrameworksCxx.api
index c06d3fc44d2a..40d47068ebce 100644
--- a/scripts/cxx-api/api-snapshots/ReactCommonFrameworksCxx.api
+++ b/scripts/cxx-api/api-snapshots/ReactCommonFrameworksCxx.api
@@ -8143,13 +8143,13 @@ constexpr bool facebook::yoga::operator>=(facebook::yoga::FloatOptional lhs, fac
 constexpr facebook::yoga::FloatOptional facebook::yoga::operator+(facebook::yoga::FloatOptional lhs, facebook::yoga::FloatOptional rhs);
 
 class facebook::yoga::Config : public YGConfig {
-  public Config(YGLogger logger);
   public YGNodeRef cloneNode(YGNodeConstRef node, YGNodeConstRef owner, size_t childIndex) const;
   public bool hasErrata(facebook::yoga::Errata errata) const;
   public bool useWebDefaults() const;
+  public constexpr Config(YGLogger logger);
   public facebook::yoga::Errata getErrata() const;
   public float getPointScaleFactor() const;
-  public static const facebook::yoga::Config& getDefault();
+  public static constexpr const facebook::yoga::Config& getDefault();
   public uint32_t getVersion() const noexcept;
   public void addErrata(facebook::yoga::Errata errata);
   public void log(const facebook::yoga::Node* node, facebook::yoga::LogLevel logLevel, const char* format, va_list args) const;
diff --git a/scripts/cxx-api/api-snapshots/ReactCommonNewarchCxx.api b/scripts/cxx-api/api-snapshots/ReactCommonNewarchCxx.api
index 1da6bfffd246..845fb97ab917 100644
--- a/scripts/cxx-api/api-snapshots/ReactCommonNewarchCxx.api
+++ b/scripts/cxx-api/api-snapshots/ReactCommonNewarchCxx.api
@@ -3788,13 +3788,13 @@ constexpr bool facebook::yoga::operator>=(facebook::yoga::FloatOptional lhs, fac
 constexpr facebook::yoga::FloatOptional facebook::yoga::operator+(facebook::yoga::FloatOptional lhs, facebook::yoga::FloatOptional rhs);
 
 class facebook::yoga::Config : public YGConfig {
-  public Config(YGLogger logger);
   public YGNodeRef cloneNode(YGNodeConstRef node, YGNodeConstRef owner, size_t childIndex) const;
   public bool hasErrata(facebook::yoga::Errata errata) const;
   public bool useWebDefaults() const;
+  public constexpr Config(YGLogger logger);
   public facebook::yoga::Errata getErrata() const;
   public float getPointScaleFactor() const;
-  public static const facebook::yoga::Config& getDefault();
+  public static constexpr const facebook::yoga::Config& getDefault();
   public uint32_t getVersion() const noexcept;
   public void addErrata(facebook::yoga::Errata errata);
   public void log(const facebook::yoga::Node* node, facebook::yoga::LogLevel logLevel, const char* format, va_list args) const;
diff --git a/scripts/cxx-api/api-snapshots/ReactCommonReleaseCxx.api b/scripts/cxx-api/api-snapshots/ReactCommonReleaseCxx.api
index 1da6bfffd246..845fb97ab917 100644
--- a/scripts/cxx-api/api-snapshots/ReactCommonReleaseCxx.api
+++ b/scripts/cxx-api/api-snapshots/ReactCommonReleaseCxx.api
@@ -3788,13 +3788,13 @@ constexpr bool facebook::yoga::operator>=(facebook::yoga::FloatOptional lhs, fac
 constexpr facebook::yoga::FloatOptional facebook::yoga::operator+(facebook::yoga::FloatOptional lhs, facebook::yoga::FloatOptional rhs);
 
 class facebook::yoga::Config : public YGConfig {
-  public Config(YGLogger logger);
   public YGNodeRef cloneNode(YGNodeConstRef node, YGNodeConstRef owner, size_t childIndex) const;
   public bool hasErrata(facebook::yoga::Errata errata) const;
   public bool useWebDefaults() const;
+  public constexpr Config(YGLogger logger);
   public facebook::yoga::Errata getErrata() const;
   public float getPointScaleFactor() const;
-  public static const facebook::yoga::Config& getDefault();
+  public static constexpr const facebook::yoga::Config& getDefault();
   public uint32_t getVersion() const noexcept;
   public void addErrata(facebook::yoga::Errata errata);
   public void log(const facebook::yoga::Node* node, facebook::yoga::LogLevel logLevel, const char* format, va_list args) const;