NibInstantiatable

ComplexWay.swift

import UIKit

public protocol NibInstantiator {
    associatedtype Base
    func instantiate() -> Base
}

public extension NibInstantiator where Base: UIView {
    public func instantiate() -> Base {
        guard let view =
            UINib(nibName: String(describing: Base.self), bundle: Bundle(for: Base.self))
                .instantiate(withOwner: nil, options: nil)
                .first as? Base else { fatalError("Can not load \(Base.self) from xib") }
        return view
    }
}

public struct NibInstantiatorType<T: UIView>: NibInstantiator { public typealias Base = T }

public protocol NibInstantiatable {
    associatedtype T: UIView
    static var instantiator: NibInstantiatorType<T> { get }
}

public extension NibInstantiatable where Self: UIView {
    static var instantiator: NibInstantiatorType<Self> { return NibInstantiatorType<Self>() }
}

extension UITableView: NibInstantiatable {}
extension UICollectionView: NibInstantiatable {}

SimpleWay.swift

import UIKit

public protocol NibInstantiatable: class {}

public extension UIView {
    public static func instantiate<T>() -> T
        where T: NibInstantiatable {
        guard let view =
            UINib(nibName: String(describing: T.self), bundle: Bundle(for: T.self))
                .instantiate(withOwner: nil, options: nil)
                .first as? T else { fatalError("Can not load \(T.self) from xib") }
        return view
    }
}

extension UITableView: NibInstantiatable {}
extension UICollectionView: NibInstantiatable {}