react-native-navigation/lib/ios/RNNReactRootView.m

#import "RNNReactRootView.h"

@implementation RNNReactRootView

- (void)setRootViewDidChangeIntrinsicSize:(void (^)(CGSize))rootViewDidChangeIntrinsicSize {
	_rootViewDidChangeIntrinsicSize = rootViewDidChangeIntrinsicSize;
	self.delegate = self;
}

- (void)rootViewDidChangeIntrinsicSize:(RCTRootView *)rootView {
	if (_rootViewDidChangeIntrinsicSize) {
		_rootViewDidChangeIntrinsicSize(rootView.intrinsicContentSize);
	}
}

- (void)setAlignment:(NSString *)alignment {
	if ([alignment isEqualToString:@"fill"]) {
		self.sizeFlexibility = RCTRootViewSizeFlexibilityNone;
	} else {
		self.sizeFlexibility = RCTRootViewSizeFlexibilityWidthAndHeight;
	}
}

@end