To register and dequeue cells.

ReusableViews+Extension.swift

public extension UIView {
    class var identifier: String {
        String(describing: self)
    }
}

public extension UITableView {
    func registerNib(_ type: UITableViewCell.Type, bundle: Bundle) {
        register(
            UINib(nibName: type.identifier, bundle: bundle),
            forCellReuseIdentifier: type.identifier
        )
    }

    func dequeueCell<CellType: UITableViewCell>(type: CellType.Type, indexPath: IndexPath) -> CellType {
        guard let cell = dequeueReusableCell(withIdentifier: CellType.identifier, for: indexPath) as? CellType else {
            fatalError("Wrong type of cell \(type)")
        }
        return cell
    }

    func dequeueHeaderFooter<Header: UITableViewHeaderFooterView>(type: Header.Type) -> Header {
        guard let view = dequeueReusableHeaderFooterView(withIdentifier: Header.identifier) as? Header else {
            fatalError("Wrong type of header/footer view \(type)")
        }
        return view
    }
}

public extension UICollectionView {
    func registerNib(_ type: UICollectionViewCell.Type, bundle: Bundle) {
        register(
            UINib(nibName: type.identifier, bundle: bundle),
            forCellWithReuseIdentifier: type.identifier
        )
    }

    func registerHeader(_ type: UICollectionReusableView.Type, bundle: Bundle) {
        register(
            UINib(nibName: type.identifier, bundle: bundle),
            forSupplementaryViewOfKind: UICollectionView.elementKindSectionHeader, withReuseIdentifier: type.identifier
        )
    }

    func dequeueCell<CellType: UICollectionViewCell>(type: CellType.Type, indexPath: IndexPath) -> CellType {
        guard let cell = dequeueReusableCell(
            withReuseIdentifier: CellType.identifier, for: indexPath
        ) as? CellType else {
            fatalError("Wrong type of cell \(type)")
        }
        return cell
    }

    func dequeueHeaderView<ViewType: UICollectionReusableView>(type: ViewType.Type, indexPath: IndexPath) -> ViewType {
        guard let headerView = dequeueReusableSupplementaryView(
            ofKind:
            UICollectionView.elementKindSectionHeader,
            withReuseIdentifier: ViewType.identifier,
            for: indexPath
        ) as? ViewType else {
            fatalError("Wrong type of header view \(type)")
        }
        return headerView
    }
}