From 52e7313f14b1fa5c0c2b43b1a9309646b41e0bed Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rub=C3=A9n=20Norte?= <rubennorte@meta.com>
Date: Thu, 29 Feb 2024 14:16:16 +0000
Subject: [PATCH] [RN] Use microtasks when using bridgeless mode in React
 Native Fabric renderer (OSS version)

---
 .eslintrc.js                                          | 6 ++++++
 packages/shared/forks/ReactFeatureFlags.native-oss.js | 5 ++++-
 scripts/flow/react-native-host-hooks.js               | 2 ++
 scripts/rollup/validate/eslintrc.rn.js                | 2 ++
 4 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/.eslintrc.js b/.eslintrc.js
index 7bb59ee17f0c6..fed5a65f40369 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -429,6 +429,12 @@ module.exports = {
         nativeFabricUIManager: 'readonly',
       },
     },
+    {
+      files: ['packages/shared/forks/**/*.js'],
+      globals: {
+        RN$Bridgeless: 'readonly',
+      },
+    },
     {
       files: ['packages/react-server-dom-webpack/**/*.js'],
       globals: {
diff --git a/packages/shared/forks/ReactFeatureFlags.native-oss.js b/packages/shared/forks/ReactFeatureFlags.native-oss.js
index 1db47db31b857..70d1d3b5604c1 100644
--- a/packages/shared/forks/ReactFeatureFlags.native-oss.js
+++ b/packages/shared/forks/ReactFeatureFlags.native-oss.js
@@ -82,7 +82,10 @@ export const enableAsyncActions = false;
 
 export const alwaysThrottleRetries = false;
 
-export const useMicrotasksForSchedulingInFabric = false;
+const isBridgeless: boolean =
+  typeof RN$Bridgeless !== 'undefined' && !!RN$Bridgeless;
+
+export const useMicrotasksForSchedulingInFabric = isBridgeless;
 export const passChildrenWhenCloningPersistedNodes = false;
 export const enableUseDeferredValueInitialArg = __EXPERIMENTAL__;
 export const disableClientCache = true;
diff --git a/scripts/flow/react-native-host-hooks.js b/scripts/flow/react-native-host-hooks.js
index a6e41c2a51e1c..81fe56a75857a 100644
--- a/scripts/flow/react-native-host-hooks.js
+++ b/scripts/flow/react-native-host-hooks.js
@@ -167,6 +167,8 @@ declare module 'react-native/Libraries/ReactPrivate/ReactNativePrivateInterface'
 declare module 'react-native/Libraries/ReactPrivate/ReactNativePrivateInitializeCore' {
 }
 
+declare const RN$Bridgeless: boolean;
+
 // This is needed for a short term solution.
 // See https://github.com/facebook/react/pull/15490 for more info
 declare var nativeFabricUIManager: {
diff --git a/scripts/rollup/validate/eslintrc.rn.js b/scripts/rollup/validate/eslintrc.rn.js
index ff956ec5e746c..d302296721e51 100644
--- a/scripts/rollup/validate/eslintrc.rn.js
+++ b/scripts/rollup/validate/eslintrc.rn.js
@@ -42,6 +42,8 @@ module.exports = {
     // Fabric. See https://github.com/facebook/react/pull/15490
     // for more information
     nativeFabricUIManager: 'readonly',
+    // RN Bridgeless mode flag
+    RN$Bridgeless: 'readonly',
     // Trusted Types
     trustedTypes: 'readonly',
     // RN supports this