Simple instantiateViewControllerWithIdentifier category

UIViewController+StoryboardInstantiable.h

#import <UIKit/UIKit.h>

@protocol StoryboardInstantiable <NSObject>

+ (NSString *)storyboardID;

@end

@interface UIViewController (StoryboardInstantiable)

+ (UIViewController *)instanceByStoryboardID:(NSString *)storyboardID andError:(NSError **)error;
+ (UIViewController *)instanceByStoryboardID:(NSString *)storyboardID;

@end

UIViewController+StoryboardInstantiable.m

#import "UIViewController+StoryboardInstantiable.h"

@implementation UIViewController (StoryboardInstantiable)

+ (UIViewController *)instanceByStoryboardID:(NSString *)storyboardID andError:(NSError **)error {
    if (![self conformsToProtocol:@protocol(StoryboardInstantiable)]) {
        NSDictionary *d = [NSDictionary dictionaryWithObject:@"Class does not comfort <StoryboardInstantiable> protocol" forKey:NSLocalizedDescriptionKey];
        *error = [[NSError alloc] initWithDomain:@"ru.domain" code:-1 userInfo:d];
        return nil;
    }
    
    UIStoryboard *sb = [UIStoryboard storyboardWithName:storyboardID bundle:nil];
    return [sb instantiateViewControllerWithIdentifier:[(id<StoryboardInstantiable>)self storyboardID]];
}

+ (UIViewController *)instanceByStoryboardID:(NSString *)storyboardID {
    UIStoryboard *sb = [UIStoryboard storyboardWithName:storyboardID bundle:nil];
    return [sb instantiateViewControllerWithIdentifier:[(id<StoryboardInstantiable>)self storyboardID]];
}

@end