skip to content
Andrei Calazans

React Native Weekly - W10 2022

/ 4 min read

This is the 45th edition of the React Native Weekly. It covers updates from 28th February to 6th of March.

This week includes 48 commits from 23 distinct authors.


  • Added Runtime.getHeadUsage for Hermes
  • Introduce viewRegistry_DEPRECATED addUIBlock for Fabric migration
  • Added Event and CustomEvent W3c-compatible polyfills

Include folly fabric headers in source files [iOS] [Fabric]

Danilo Bürger fixed a compilation issue on iOS when including react-native-safe-area-context 4.0.1 with Fabric enabled.

diff --git a/third-party-podspecs/RCT-Folly.podspec b/third-party-podspecs/RCT-Folly.podspec
index 0ae3060bdc8..700cd7e2cfb 100644
--- a/third-party-podspecs/RCT-Folly.podspec
+++ b/third-party-podspecs/RCT-Folly.podspec
@@ -91,7 +91,11 @@ do |spec|
-                          'folly/portability/Malloc.cpp'
+                          'folly/portability/Malloc.cpp',
+                          'folly/concurrency/CacheLocality.h',
+                          'folly/synchronization/ParkingLot.h',
+                          'folly/synchronization/SanitizeThread.h',
+                          'folly/system/ThreadId.h'

Performance logger concurrent mode annotation

The performance logger will now contain an annotation to tag if in concurrent mode.

diff --git a/Libraries/ReactNative/renderApplication.js b/Libraries/ReactNative/renderApplication.js
index 5663a47a7ad..d3f2d87971d 100644
--- a/Libraries/ReactNative/renderApplication.js
+++ b/Libraries/ReactNative/renderApplication.js
@@ -64,6 +64,10 @@ function renderApplication<Props: Object>(

+  performanceLogger.setExtra(
+    'usedReactConcurrentRoot',
+    useConcurrentRoot ? '1' : '0',
+  );

Added Runtime.getHeadUsage for Hermes

Janic Duplessis added Runtime.getHeapUsage for Hermes Chrome inspector.

This will enable seeing a summary of memory usage from JavaScript in Devtools.

Migrating codegenNativeComponent to be Bridgeless compatible

Paige Sun migrated the codegenNativeComponent to be Bridgeless compatible.

We learn to use UIManager.hasViewManagerConfig to check the existence of a view manager instead of UIManager.getViewManagerConfig to be bridgeless compatible.

Introduce _viewRegistry_DEPRECATED addUIBlock for Fabric migration

Paige Sun added _viewRegistry_DEPRECATED addUIBlock to make it easier to migrate View Managers to Fabric.

With Fabric the UIManager will no longer exist, and the use uiManager addUIBlock will need to be replaced by _viewRegistry_DEPRECATED addUIBlock.

Paige also exemplified the migration to “Bridgeless” mode with the DatePickerIOS.

Fix transform when calculate overflowInset

This contribution is a clear example of how the shared C++ interface benefits from work focused on one of the platforms - Android.

Xin Chen fixed overflowInset calculation when a shadow node has transform matrix from a transform prop in JS.

note how Xin has made various improvements to Android which seem related to supporting VR based on what I’ve followed so far.

Xin’s commit message goes into great detail into the problem he faced plus fix.

Improve rendering of images when resampled and corner radius applied [Android]

Pieter De Baets improved rendering images by enabling paintFilterBitmap when rendering images with rounded corners.

Guarantee configureNdkBild depends on preBuild task [Android]

According to Nicola Corti, due to a bug with AGP, the configureNdkBuild* tasks are not depending on preBuild tasks. Thus, Nicola added a fix which manually guarantees this dependency.

Added Event and CustomEvent W3c-compatible polyfills

Joshua Gross added these polyfills in preparation for upcoming changes.

Fixed error caused by re-registering bubbling event by RCTModalHostView

According HeyImChris they are seeing the following error Component 'RCTModalHostView' re-registered bubbling event 'topDismiss' as a direct event moduleConstantsForComponent on a react-native-macOS build.

This is fixed by replacing RCTBubblingEventBlock for RCTDirectEventBlock.

diff --git a/React/Views/RCTModalHostView.h b/React/Views/RCTModalHostView.h
index 0246328f99f..2fcdcaea83f 100644
--- a/React/Views/RCTModalHostView.h
+++ b/React/Views/RCTModalHostView.h
@@ -38,7 +38,7 @@
 @property (nonatomic, copy) RCTDirectEventBlock onOrientationChange;

 // Fabric only
-@property (nonatomic, copy) RCTBubblingEventBlock onDismiss;
+@property (nonatomic, copy) RCTDirectEventBlock onDismiss;

Setup a Gradle build inside ReactAndroid/hermes-engine to download Hermes sources

Adapted from Nicola’s commit message, Nicola Corti started a Gradle build inside ReactAndroid/hermes-engine to kickoff a small project where we can download Hermes sources and start a compilation of Hermes sources from there.

Added asBool() method to JSI Value

Scott Kyle added the asBool() method to the JSI object for easier conversion of data.

Allow usage of TurboModules in context with RTTI

Nikita Lutsenko moved the definitions of TurboModule’s virtual methods to declaration to allow for use in context with RTTI.

Library upgrades


  • TypeScript Weekly: The best TypeScript links every week, right in your inbox.
  • This Week In React: the best of React & React Native news. Sebastien filters the noise, and you save time!
  • News: learn about the latest in JavaScript and cross-platform tools.
  • Tailwind Weekly: all things Tailwind CSS, new issue every Saturday.


If you want to see more checkout the previous week’s posts here. Subscribe to get notified when new posts are out = )