Main.storyboard からインスタンス生成するための Extension

UIStoryboard+Main.swift

import UIKit


extension UIStoryboard {
    static func mainInstantiate<T>(withViewController type: T.Type) -> T where T: UIViewController {
        let storyboard = UIStoryboard(name: "Main", bundle: nil)
        guard let controller = storyboard.instantiateViewController(withIdentifier: type.storyboardIdentifier) as? T else {
            fatalError("Could not instantiate view controller with type \(T.self)")
        }
        return controller
    }
}

extension UIViewController {
    static var storyboardIdentifier: String {
        return String(describing: self)
    }
}