Type-safe-tableViewCell3.swift

protocol Reusable: class {
    static var reusableIdentifier: String { get }
}

extension Reusable {
    static var reusableIdentifier: String {
        return String(describing: self)
    }
}

protocol NibReusable: Reusable {
    static var nib: UINib { get }
}

extension NibReusable {
    static var nib: UINib {
        let nibName = String(describing: self)
        return UINib(nibName: nibName, bundle: Bundle(for: self))
    }
}