Swift 5 - MVVM - ViewController, ViewModel, Model, Datasource, Webservice

EmployeeApiService.swift

import Foundation

class APIService :  NSObject {
    private let sourcesURL = URL(string: "http://dummy.restapiexample.com/api/v1/employees")!
    
    func apiToGetEmployeeData(completion : @escaping (Employees) -> ()){   
        URLSession.shared.dataTask(with: sourcesURL) { (data, urlResponse, error) in
            if let data = data {
                let jsonDecoder = JSONDecoder()
                let empData = try! jsonDecoder.decode(Employees.self, from: data)
                    completion(empData)
            }
            
        }.resume()
    }   
}

Employees.swift

import Foundation

struct Employees: Decodable {
    let status: String
    let data: [EmployeeData]
}

struct EmployeeData: Decodable {
    let id, employeeName, employeeSalary, employeeAge: String
    let profileImage: String

    enum CodingKeys: String, CodingKey {
        case id
        case employeeName = "employee_name"
        case employeeSalary = "employee_salary"
        case employeeAge = "employee_age"
        case profileImage = "profile_image"
    }
}

EmployeesViewModel.swift

import Foundation

class EmployeesViewModel : NSObject {
    
    private var apiService : APIService!
    private(set) var empData : Employees! {
        didSet {
            self.bindEmployeeViewModelToController()
        }
    }
    
    var bindEmployeeViewModelToController : (() -> ()) = {}
    
    override init() {
        super.init()
        self.apiService =  APIService()
        callFuncToGetEmpData()
    }
    
    func callFuncToGetEmpData() {
        self.apiService.apiToGetEmployeeData { (empData) in
            self.empData = empData
        }
    }
}

EmployeeTableViewCell.swift

import UIKit

class EmployeeTableViewCell: UITableViewCell {
    @IBOutlet weak var employeeIdLabel: UILabel!
    @IBOutlet weak var employeeNameLabel: UILabel!
    
    var employee : EmployeeData? {
        didSet {
            employeeIdLabel.text = employee?.id
            employeeNameLabel.text = employee?.employeeName
        }
    }
    
    override func awakeFromNib() {
        super.awakeFromNib()
    }

    override func setSelected(_ selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)
    }
}

EmployeeTableViewController.swift

import UIKit

class EmployeeTableViewController: UIViewController {
    
    @IBOutlet weak var employeeTableView: UITableView!
    
    private var employeeViewModel : EmployeesViewModel!
    private var dataSource : EmployeeTableViewDataSource<EmployeeTableViewCell,EmployeeData>!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        callToViewModelForUIUpdate()
    }
    
    func callToViewModelForUIUpdate(){
        
        self.employeeViewModel =  EmployeesViewModel()
        self.employeeViewModel.bindEmployeeViewModelToController = {
            self.updateDataSource()
        }
    }
    
    func updateDataSource(){
        self.dataSource = EmployeeTableViewDataSource(cellIdentifier: "EmployeeTableViewCell", items: self.employeeViewModel.empData.data, configureCell: { (cell, evm) in
            cell.employeeIdLabel.text = evm.id
            cell.employeeNameLabel.text = evm.employeeName
        })
        
        DispatchQueue.main.async {
            self.employeeTableView.dataSource = self.dataSource
            self.employeeTableView.reloadData()
        }
    }
}

EmployeeTableViewDataSource.swift

import Foundation
import UIKit

class EmployeeTableViewDataSource<CELL : UITableViewCell,T> : NSObject, UITableViewDataSource {
    
    private var cellIdentifier : String!
    private var items : [T]!
    var configureCell : (CELL, T) -> () = {_,_ in }
    
    
    init(cellIdentifier : String, items : [T], configureCell : @escaping (CELL, T) -> ()) {
        self.cellIdentifier = cellIdentifier
        self.items =  items
        self.configureCell = configureCell
    }
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        items.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        
         let cell = tableView.dequeueReusableCell(withIdentifier: cellIdentifier, for: indexPath) as! CELL
        
        let item = self.items[indexPath.row]
        self.configureCell(cell, item)
        return cell
    }
}