Native Side Set React Native I18nManager before the JS Bundle Kicks Off

AppDelegate.mm

// Modify "didFinishLaunchingWithOptions" method in IOS AppDelegate.mm

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
// Ahmed Rowihi: Native Side I18n hack :D
// set React Native I18nManager before the JS Bundle Kicks Off!
  NSString *value = [[NSUserDefaults standardUserDefaults] stringForKey:@"@user_language"];
  BOOL isRTL = [value isEqualToString:@"ar"] || [[[NSLocale preferredLanguages] objectAtIndex:0] hasPrefix:@"ar_"];
  if (isRTL) {
      NSLocale *locale = [[NSLocale alloc] initWithLocaleIdentifier:@"ar"];
      [[NSUserDefaults standardUserDefaults] setObject:@[locale.localeIdentifier] forKey:@"AppleLanguages"];
      [[NSUserDefaults standardUserDefaults] setObject:locale.localeIdentifier forKey:@"AppleLocale"];
      [[NSUserDefaults standardUserDefaults] synchronize];
  } else {
      [[NSUserDefaults standardUserDefaults] setObject:nil forKey:@"AppleLanguages"];
      [[NSUserDefaults standardUserDefaults] setObject:nil forKey:@"AppleLocale"];
      [[NSUserDefaults standardUserDefaults] synchronize];
  }
      [[RCTI18nUtil sharedInstance] allowRTL:isRTL];
      [[RCTI18nUtil sharedInstance] forceRTL:isRTL];

// ... your rest of default code before RCTAppSetupPrepareApp(application);

MainApplication.java

// Modify onCreate() in Android MainApplication.java
  @Override
  public void onCreate() {
    super.onCreate();
    //  @ahmedrowaihi: Native Side I18n hack :D
    // set React Native I18nManager before the JS Bundle Kicks Off!
      String value = null;
      try {
          value = AsyncLocalStorageUtil.getItemImpl(
                  ReactDatabaseSupplier.getInstance(this).get(),
                  "@user_language");
          if (value == null) value = Locale.getDefault().getLanguage();
          boolean isRTL = "ar".equals(value);
          Locale locale = new Locale(value);
          Configuration config = getBaseContext().getResources().getConfiguration();
          config.setLocale(locale);
          I18nUtil sharedI18nUtilInstance = I18nUtil.getInstance();
          sharedI18nUtilInstance.allowRTL(this, isRTL);
          sharedI18nUtilInstance.forceRTL(this, isRTL);
      } catch (Exception ignored) {}

      // ... your rest of default code before react host
      // new ReactNativeHostWrapper(this, new MainApplicationReactNativeHost(this));
  }