Expo's tree shaking crashes production with latest react-native-reanimated #41620
Description
Minimal reproducible example
https://github.com/RohovDmytro/expo-shaken-reanimated
Steps to reproduce
App crashes when tree shaken enabled. Not sure if its due to side effects in reanimated or due to unstable nature of tree shaking as a feature flag.
Steps to reproduce
There’s a problem with pairing expo’s unstable feature flags with latest react-native-reanimated version.
-
New expo project
-
Set up tree shaking via
.env:
EXPO_UNSTABLE_METRO_OPTIMIZE_GRAPH=1
EXPO_UNSTABLE_TREE_SHAKING=1
EXPO_UNSTABLE_WEB_MODAL=1- Add
yarn add react-native-reanimated@4.2.0 react-native-worklets@0.7.1x-
Wrap the App.js with an
Animate.Viewcomponent to make sure reanimated stays in the bundle. -
Build an Android release build.
-
Crash:
{ [WorkletsError: [Worklets] Native part of Worklets doesn't seem to be initialized.Environment
expo-env-info 2.0.8 environment info:
System:
OS: macOS 26.2
Shell: 5.9 - /bin/zsh
Binaries:
Node: 24.11.1 - ~/.nvm/versions/node/v24.11.1/bin/node
Yarn: 1.22.15 - /usr/local/bin/yarn
npm: 11.6.2 - ~/.nvm/versions/node/v24.11.1/bin/npm
Watchman: 2025.11.10.00 - /opt/homebrew/bin/watchman
Managers:
CocoaPods: 1.16.2 - /opt/homebrew/bin/pod
SDKs:
iOS SDK:
Platforms: DriverKit 25.2, iOS 26.2, macOS 26.2, tvOS 26.2, visionOS 26.2, watchOS 26.2
Android SDK:
API Levels: 33, 34, 35, 36
Build Tools: 35.0.0, 36.0.0, 36.1.0
System Images: android-31 | Google Play ARM 64 v8a
IDEs:
Android Studio: 2025.2 AI-252.27397.103.2522.14514259
Xcode: 26.2/17C52 - /usr/bin/xcodebuild
npmPackages:
expo: ~54.0.29 => 54.0.29
react: 19.1.0 => 19.1.0
react-native: 0.81.5 => 0.81.5
Expo Workflow: bare
Expo Doctor Diagnostics
✖ Check that packages match versions required by installed Expo SDK
⚠️ Minor version mismatches
package expected found
react-native-reanimated ~4.1.1 4.2.0
react-native-worklets 0.5.1 0.7.1
2 packages out of date.
Advice:
Use 'npx expo install --check' to review and upgrade your dependencies.
To ignore specific packages, add them to "expo.install.exclude" in package.json. Learn more: https://expo.fyi/dependency-validation
2 checks failed, indicating possible issues with the project.