Ensure you are using the latest stable release. Check the Software Mansion Reanimated Issues Page to verify if your specific package version requires a patch. Run the following to update:
C++ Exception: N8facebook3jsi7JSErrorE: ExceptionsManager.reportException raised an exception: Unhandled JS Exception: TypeError: Cannot read property 'localeCompare' of undefined
A Worklet is trying to update a sharedValue or animate a component that has already been unmounted.
This indicates that an unhandled was thrown inside the JavaScript Interface (JSI) layer of your application. Because the native iOS environment cannot map the raw JavaScript stack trace to C++ directly, it surfaces as a generic, fatal C++ exception. It most commonly shows up when your JavaScript engine (like Hermes) encounters a major issue while executing code triggered by a native thread. Root Causes of the Error
To resolve this "best," developers should follow a systematic approach: Verify Native Linking : Use tools like the React Native Upgrade Helper to ensure your AppDelegate.mm MainApplication.java n8facebook3jsi7jserrore best
Downgrading or improperly upgrading react-native-reanimated is the most common cause, especially when moving between version 3.4.2 and 3.5.x. 2. Gesture Handler Conflicts
By anticipating the specific error codes (190, 4, 100) that Facebook returns, you transform a fragile script into a resilient automation.
The involve updating native reanimation frameworks, modernizing JSI error handling methods, and implementing robust global boundaries. Root Causes of the Error
The code snippet N8facebook3jsi7JSErrorE is a specific C++ exception frequently encountered by developers using React Native Facebook's JSI Ensure you are using the latest stable release
By following these tips and best practices, you should be able to resolve common errors and get the most out of Facebook's JavaScript SDK.
Because this error is a container for any unhandled JavaScript crash passing through the JSI, it can be triggered by several distinct sub-systems:
: If the latest version doesn't work, some developers reported success by downgrading to a known stable version like Sentry Configuration
: Ensure react-native-reanimated is on the latest stable version. This indicates that an unhandled was thrown inside
To resolve crashes associated with N8facebook3jsi7JSErrorE , developers on platforms like GitHub suggest the following:
version. Downgrading to a stable release or ensuring your worklets are properly configured often fixes it. #ReactNative #CodingLife #HermesEngine Option 3: For Internal Documentation/Slack Use this to help your team identify the error. Heads up on N8facebook3jsi7JSErrorE We are seeing an uptick in N8facebook3jsi7JSErrorE errors in our latest build. What it is: A mangled C++ name for facebook::jsi::JSError The Issue:
Third-party analytics or survey SDKs—such as the Refiner Mobile SDK or the MetaMask Mobile App wrapper—sometimes trigger this crash on iOS if they interact with the React Native bridge before it is fully ready. Best Practices to Fix N8facebook3jsi7JSErrorE 1. Upgrade React Native Reanimated