Example of simple UITableViewDataSource with configurable sections

SectionsExample.swift

import UIKit

protocol ModelProtocol {

}

class ModelA: ModelProtocol {

}

class ModelB: ModelProtocol {

}

protocol CellProtocol {
    func setup(model: ModelProtocol)
}

protocol CellProtocolTyped: CellProtocol {
    associatedtype Model: ModelProtocol
    func configure(model: Model)
}

extension CellProtocolTyped {
    func setup(model: ModelProtocol) {
        if let model = model as? Model {
            configure(model: model)
        }
    }
}

class CellA: UITableViewCell, CellProtocolTyped {
    func configure(model: ModelA) {

    }
}

class CellB: UITableViewCell, CellProtocolTyped {
    func configure(model: ModelB) {

    }
}

class SectionsExample: UIViewController, UITableViewDataSource {
    struct Section {
        var title = ""
        var items: [ModelProtocol] = []
    }

    var sections: [Section] = []

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        sections = [
            Section(title: "a", items: [ModelA(), ModelA()]),
            Section(title: "a", items: [ModelA(), ModelB()])
        ]

        let shouldShowLastSection = true
        if shouldShowLastSection {
            sections.append(Section(title: "last", items: []))
        }
    }

    func numberOfSections(in tableView: UITableView) -> Int {
        return sections.count
    }

    func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
        let sectionModel = sections[section]
        return sectionModel.title
    }

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        let sectionModel = sections[section]
        return sectionModel.items.count
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let model = sections[indexPath.section].items[indexPath.row]
        let identifier = "\(type(of: model))"
        let cell = tableView.dequeueReusableCell(withIdentifier: identifier, for: indexPath)

        if let cellProtocol = cell as? CellProtocol {
            cellProtocol.setup(model: model)
        }

        return cell
    }
}