Init based Storyboard View Controller Instantiation

SampleViewController.swift

final class SampleViewController: StoryboardBackedViewController {
    // Unfortunately this must be an IUO var, so that we can set the value after super.init
    private var member: Foo!
    
    // Proper dependency injection in a storyboard backed VC!
    init(foo: Foo) {
        super.init(storyboardIdentifier: "SampleViewControllerIdentifier")

        // We have to set the members *after* calling super.init, since it changes the instance of `self`.
        self.member = foo
    }
}

StoryboardBackedViewController.h

//
//  StoryboardBackedViewController.h
//  Fabric
//
//  Created by Javier Soto on 9/6/15.
//  Copyright © 2015 Fabric. All rights reserved.
//

#import <UIKit/UIKit.h>

NS_ASSUME_NONNULL_BEGIN

@interface StoryboardBackedViewController : UIViewController

// This method returns a different instance of self, so properties on self must be set *after* calling this initializer.
- (instancetype)initWithStoryboardIdentifier:(NSString *)storyboardIdentifier NS_DESIGNATED_INITIALIZER;

#pragma mark - Unavailable

- (instancetype)initWithNibName:(NSString * _Nullable)nibNameOrNil bundle:(NSBundle * _Nullable)nibBundleOrNil NS_UNAVAILABLE;
- (_Nullable instancetype)initWithCoder:(NSCoder *)aDecoder NS_UNAVAILABLE;
- (instancetype)init NS_UNAVAILABLE;

@end

NS_ASSUME_NONNULL_END

StoryboardBackedViewController.m

//
//  StoryboardBackedViewController.m
//  Fabric
//
//  Created by Javier Soto on 9/6/15.
//  Copyright © 2015 Fabric. All rights reserved.
//

#import "StoryboardBackedViewController.h"

@interface UIStoryboard (FABMainStoryboard)

+ (instancetype)fab_mainStoryboard;

@end

@implementation UIStoryboard (FABMainStoryboard)

+ (instancetype)fab_mainStoryboard {
    return [self storyboardWithName:@"Main" bundle:nil];
}

@end

// Instantiating controllers from UIStoryboard is a horrible API that breaks that designated initializer chain.
// Implementing this in Obj-C so that we can inherit from this and compose initializers properly.

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wobjc-designated-initializers"

- (instancetype)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    NSAssert(NO, @"Must use -%@", NSStringFromSelector(@selector(initWithStoryboardIdentifier:)));

    return nil;
}

- (instancetype)initWithStoryboardIdentifier:(NSString *)storyboardIdentifier {
    return [[UIStoryboard fab_mainStoryboard] instantiateViewControllerWithIdentifier:storyboardIdentifier];
}

@end

#pragma clang diagnostic pop