bugsnag/bugsnag-js

#import "BugsnagReactNativePlugin.h"

#import "BugsnagInternals.h"

//
// BugsnagReactNativePlugin is instantiated by bugsnag-cocoa during its startup:
// https://github.com/bugsnag/bugsnag-cocoa/blob/v6.16.6/Bugsnag/Client/BugsnagClient.m#L355-L365
//
// This makes it the ideal place for configuring the native layer before it sends any events.
//
@implementation BugsnagReactNativePlugin

- (void)load:(BugsnagClient *)client {
    //
    // When using the old architecture, React Native catches JS exceptions and calls RCTFatal() to raise an Objective-C exception in response.
    // These need to be ignored because Bugsnag's JS layer also catches JS exceptions, via a different mechanism.
    //
    // RCTFatal() sets the exception name to "RCTFatalException: ${error.localizedDescription}"
    // https://github.com/facebook/react-native/blob/v0.68.0/React/Base/RCTAssert.m#L132
    //
    // For JS errors the localizedDescription is @"Unhandled JS Exception: ${message}"
    // https://github.com/facebook/react-native/blob/v0.68.0/React/CoreModules/RCTExceptionsManager.mm#L66
    // https://github.com/facebook/react-native/blob/v0.68.0/React/CxxModule/RCTCxxUtils.mm#L51
    //
    // The exception name gets recorded as the error's `errorClass`.
    //
    NSString *discardPattern = @"^RCTFatalException: Unhandled JS Exception: ";
    
    NSMutableSet *discardClasses = [client.configuration.discardClasses mutableCopy] ?: [NSMutableSet set];
    [discardClasses addObject:[NSRegularExpression regularExpressionWithPattern:discardPattern options:0 error:nil]];
    client.configuration.discardClasses = discardClasses;

    // When using the new architecture on 0.73+, these exceptions are caught and rethrown as facebook::jsi::JSError exceptions,
    // with the error message set to "Exception in HostFunction: Unhandled JS Exception: ${message}"
    // https://github.com/facebook/react-native/blob/v0.73.0/packages/react-native/ReactCommon/react/nativemodule/core/platform/ios/ReactCommon/RCTTurboModule.mm#L406
    // https://github.com/facebook/react-native/blob/v0.73.0/packages/react-native/ReactCommon/react/nativemodule/core/platform/ios/ReactCommon/RCTTurboModule.mm#L235
    
    // We can't use discardClasses here because the errorClass facebook::jsi::JSError is not specific to JS exceptions, 
    // so we need to use an onSendError block and discard based on the error message instead.
    #ifdef RCT_NEW_ARCH_ENABLED
    [client.configuration addOnSendErrorBlock:^BOOL (BugsnagEvent *event) {
        return ![event.errors[0].errorMessage hasPrefix:@"Exception in HostFunction: Unhandled JS Exception"];
    }];
    #endif
}

- (void)unload {

}

@end