How to Fix the “Invariant Violation: TurboModuleRegistry.getEnforcing(…): ‘RNCWebView’ Could Not Be Found” Error in React Native

When working with React Native, especially when integrating additional libraries like react-native-signature-canvas, encountering errors can be frustrating. One such error is:

Invariant Violation: TurboModuleRegistry.getEnforcing(...): 'RNCWebView' could not be found

This error often occurs when the necessary dependencies for a module are not properly linked or when the environment you’re using doesn’t support the required native modules. Here’s a breakdown of how I encountered and resolved this issue.

The Problem

I was working on a React Native project where I needed to add the react-native-signature-canvas library to capture user signatures. The installation process seemed straightforward:

1. Installed the package:

npm install react-native-signature-canvas

2. Since react-native-signature-canvas depends on react-native-webview, I also installed the WebView package:

npm install react-native-webview

3. I navigated to the iOS directory and ran:

cd ios

pod install

Everything seemed fine, but when I tried to run the app, I encountered the following error:

Invariant Violation: TurboModuleRegistry.getEnforcing(...): 'RNCWebView' could not be found

Troubleshooting the Issue

Initially, I spent about an hour trying to debug this issue. Here’s what I did to troubleshoot:

1. Checked the Installation: I confirmed that both react-native-signature-canvas and react-native-webview were installed correctly and that pod install completed without errors.
2. Rebuilt the Project: I tried cleaning the build folder and rebuilding the project from scratch, but the error persisted.
3. Reviewed the Documentation: I carefully re-read the documentation for both libraries to ensure that I hadn’t missed any steps.

The Solution

After some research and trial and error, I discovered the root cause of the issue: Expo Go.

• Expo Go Limitation: The Expo Go app does not support custom native modules out of the box. Since react-native-signature-canvas relies on react-native-webview, which is a native module, the error occurred because Expo Go could not find the RNCWebView module.

To resolve this issue, I did the following:

1. EAS Build: I used Expo’s EAS (Expo Application Services) to build the app with the required native modules:

eas build --platform ios

1. Running the App: Instead of using Expo Go, I ran the app directly on a simulator using:

npm run ios

After these steps, the error was resolved, and the app worked as expected.

Key Takeaways

• Expo Go is Limited: When working with native modules in React Native, remember that Expo Go cannot handle them. You’ll need to either eject from Expo Managed Workflow or use EAS Build.
• Check Dependencies: Always ensure that any dependencies required by the library are correctly installed and linked.
• Use EAS Build for Native Modules: If you’re using Expo, the easiest way to handle native modules is to use EAS Build, which allows you to include and build native code in your project.

By following these steps, you should be able to resolve the "RNCWebView" could not be found error and continue building your React Native app.

Conclusion

Encountering errors while developing in React Native is not uncommon, but with a methodical approach to troubleshooting, you can often resolve them quickly. Understanding the limitations of your development environment, such as Expo Go, can save you a lot of time and frustration. If you encounter a similar error, I hope this guide helps you find a solution faster!