[RN] Prevent unhandled JS errors from killing the process in Release

android/app/src/main/java/org/jitsi/meet/MainActivity.java

 package org.jitsi.meet;
 
-import android.os.Bundle;
-import com.crashlytics.android.Crashlytics;
 import com.facebook.react.ReactActivity;
 import com.facebook.react.ReactActivityDelegate;
 import com.facebook.react.ReactRootView;
-import io.fabric.sdk.android.Fabric;
 
 public class MainActivity extends ReactActivity {
     /**
     protected String getMainComponentName() {
         return "App";
     }
-
-    @Override
-    protected void onCreate(Bundle savedInstanceState) {
-        super.onCreate(savedInstanceState);
-
-        Fabric.with(this, new Crashlytics());
-    }
 }

android/app/src/main/java/org/jitsi/meet/MainApplication.java

 package org.jitsi.meet;
 
 import android.app.Application;
-import android.util.Log;
 
+import com.crashlytics.android.Crashlytics;
 import com.facebook.react.ReactApplication;
-import com.facebook.react.ReactInstanceManager;
 import com.facebook.react.ReactNativeHost;
 import com.facebook.react.ReactPackage;
-import com.facebook.react.shell.MainReactPackage;
-import com.oblador.vectoricons.VectorIconsPackage;
-import com.oney.WebRTCModule.WebRTCModulePackage;
+
+import io.fabric.sdk.android.Fabric;
 
 import java.util.Arrays;
 import java.util.List;
 
 public class MainApplication extends Application implements ReactApplication {
+    private final ReactNativeHost mReactNativeHost = new ReactNativeHost(this) {
+        /**
+         * {@inheritDoc}
+         */
+        @Override
+        protected boolean getUseDeveloperSupport() {
+            return BuildConfig.DEBUG;
+        }
+
+        /**
+         * {@inheritDoc}
+         */
+        @Override
+        protected List<ReactPackage> getPackages() {
+            return Arrays.<ReactPackage>asList(
+                new com.facebook.react.shell.MainReactPackage(),
+                new com.oblador.vectoricons.VectorIconsPackage(),
+                new com.oney.WebRTCModule.WebRTCModulePackage()
+            );
+        }
+    };
 
-  private final ReactNativeHost mReactNativeHost = new ReactNativeHost(this) {
+    /**
+     * {@inheritDoc}
+     */
     @Override
-    protected boolean getUseDeveloperSupport() {
-      return BuildConfig.DEBUG;
+    public ReactNativeHost getReactNativeHost() {
+        return mReactNativeHost;
     }
 
+    /**
+     * {@inheritDoc}
+     */
     @Override
-    protected List<ReactPackage> getPackages() {
-      return Arrays.<ReactPackage>asList(
-          new MainReactPackage(),
-          new VectorIconsPackage(),
-          new WebRTCModulePackage()
-      );
-    }
-  };
+    public void onCreate() {
+        super.onCreate();
 
-  @Override
-  public ReactNativeHost getReactNativeHost() {
-      return mReactNativeHost;
-  }
+        if (!getReactNativeHost()
+                .getReactInstanceManager()
+                    .getDevSupportManager()
+                        .getDevSupportEnabled()) {
+            Fabric.with(this, new Crashlytics());
+        }
+    }
 }

ios/app/AppDelegate.m

 #import "AppDelegate.h"
 #import <Crashlytics/Crashlytics.h>
 #import <Fabric/Fabric.h>
+#import "RCTAssert.h"
 #import "RCTBundleURLProvider.h"
 #import "RCTLinkingManager.h"
 #import "RCTRootView.h"
 
+/**
+ * A <tt>RCTFatalHandler</tt> implementation which swallows JavaScript errors.
+ * In the Release configuration, React Native will (intentionally) raise an
+ * unhandled NSException for an unhandled JavaScript error. This will
+ * effectively kill the application. <tt>_RCTFatal</tt> is suitable to be in
+ * accord with the Web i.e. not kill the application.
+ */
+RCTFatalHandler _RCTFatal = ^(NSError *error) {
+  id jsStackTrace = error.userInfo[RCTJSStackTraceKey];
+  @try {
+    NSString *name
+      = [NSString stringWithFormat:@"%@: %@",
+                  RCTFatalExceptionName,
+                  error.localizedDescription];
+    NSString *message
+      = RCTFormatError(error.localizedDescription, jsStackTrace, 75);
+    [NSException raise:name format:@"%@", message];
+  } @catch (NSException *e) {
+    if (!jsStackTrace) {
+      @throw;
+    }
+  }
+};
+
 @implementation AppDelegate
 
 // https://facebook.github.io/react-native/docs/linking.html
 - (BOOL)application:(UIApplication *)application
 didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
 {
+#if !DEBUG
   [Fabric with:@[[Crashlytics class]]];
 
+  // In the Release configuration, React Native will (intentionally) raise an
+  // unhandled NSException for an unhandled JavaScript error. This will
+  // effectively kill the application. In accord with the Web, do not kill the
+  // application.
+  if (!RCTGetFatalHandler()) {
+    RCTSetFatalHandler(_RCTFatal);
+  }
+#endif
+
   NSURL *jsCodeLocation
     = [[RCTBundleURLProvider sharedSettings] jsBundleURLForBundleRoot:@"index.ios"
                                                      fallbackResource:nil];

ios/app/POSIX.m

     if (0 != err) {
         NSError *error
             = [NSError errorWithDomain:NSPOSIXErrorDomain
-                  code:err
-                  userInfo:nil];
+                                  code:err
+                              userInfo:nil];
 
         reject(rejectCode, error.localizedDescription, error);
     }

react/features/app/components/App.native.js

+/* global __DEV__ */
+
 import React from 'react';
-import { Linking, Navigator } from 'react-native';
+import { Linking, Navigator, Platform } from 'react-native';
 import { Provider } from 'react-redux';
 
 import { _getRouteToRender } from '../functions';
         // Bind event handlers so they are only bound once for every instance.
         this._navigatorRenderScene = this._navigatorRenderScene.bind(this);
         this._onLinkingURL = this._onLinkingURL.bind(this);
+
+        // In the Release configuration, React Native will (intentionally) throw
+        // an unhandled JavascriptException for an unhandled JavaScript error.
+        // This will effectively kill the application. In accord with the Web,
+        // do not kill the application.
+        this._maybeDisableExceptionsManager();
     }
 
     /**
         navigator && navigator.replace({ ...route });
     }
 
+    /**
+     * Attempts to disable the use of React Native
+     * {@link ExceptionsManager#handleException} on platforms and in
+     * configurations on/in which the use of the method in questions has been
+     * determined to be undesirable. For example, React Native will
+     * (intentionally) throw an unhandled JavascriptException for an
+     * unhandled JavaScript error in the Release configuration. This will
+     * effectively kill the application. In accord with the Web, do not kill the
+     * application.
+     *
+     * @private
+     * @returns {void}
+     */
+    _maybeDisableExceptionsManager() {
+        if (__DEV__) {
+            // As mentioned above, only the Release configuration was observed
+            // to suffer.
+            return;
+        }
+        if (Platform.OS !== 'android') {
+            // A solution based on RTCSetFatalHandler was implemented on iOS and
+            // it is preferred because it is at a later step of the
+            // error/exception handling and it is specific to fatal
+            // errors/exceptions which were observed to kill the application.
+            // The solution implemented bellow was tested on Android only so it
+            // is considered safest to use it there only.
+            return;
+        }
+
+        const oldHandler = global.ErrorUtils.getGlobalHandler();
+        const newHandler = _handleException;
+
+        if (!oldHandler || oldHandler !== newHandler) {
+            newHandler.next = oldHandler;
+            global.ErrorUtils.setGlobalHandler(newHandler);
+        }
+    }
+
     /**
      * Renders the scene identified by a specific route in the Navigator of this
      * instance.
         this._openURL(event.url);
     }
 }
+
+/**
+ * Handles a (possibly unhandled) JavaScript error by preventing React Native
+ * from converting a fatal error into an unhandled native exception which will
+ * kill the application.
+ *
+ * @param {Error} error - The (possibly unhandled) JavaScript error to handle.
+ * @param {boolean} fatal - True if the specified error is fatal; otherwise,
+ * false.
+ * @private
+ * @returns {void}
+ */
+function _handleException(error, fatal) {
+    if (fatal) {
+        // In the Release configuration, React Native will (intentionally) throw
+        // an unhandled JavascriptException for an unhandled JavaScript error.
+        // This will effectively kill the application. In accord with the Web,
+        // do not kill the application.
+        console.error(error);
+    } else {
+        // Forward to the next globalHandler of ErrorUtils.
+        const next = _handleException.next;
+
+        typeof next === 'function' && next(error, fatal);
+    }
+}