React Native iOS Smooth Splash Screen (when using LaunchScreen.xib)

react-native-ios-splash.m

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
  ...
  ...
  ...

  RCTRootView *rootView = [[RCTRootView alloc] initWithBundleURL:jsCodeLocation
                                                      moduleName:@"MyAwesomeApp"
                                               initialProperties:@{}
                                                   launchOptions:launchOptions];
  



  self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
  UIViewController *rootViewController = [UIViewController new];
  rootViewController.view = rootView;
  self.window.rootViewController = rootViewController;
  [self.window makeKeyAndVisible];
  
  // re-load the LaunchScreen to prevent white screen showing before your app renders
  UIView* launchScreen =  [[[NSBundle mainBundle] loadNibNamed:@"LaunchScreen" owner:self options:nil] objectAtIndex:0];
  launchScreen.frame = [UIScreen mainScreen].bounds;
  rootView.loadingView = launchScreen;
  rootView.loadingViewFadeDelay = 0.20;
  rootView.loadingViewFadeDuration = 0.30;
  
  return YES;
}