gistfile1.txt

//
//  ImageCache.swift
//  MWN - Minimal World News
//
//  Created by Lucas Menezes on 1/22/20.
//  Copyright © 2020 Lucas Menezes. All rights reserved.
//

import UIKit


class ImageCache {
    private var dict : [String : UIImage] = [:]
    var defaultImage = UIImage()
    private func getData(from url: URL, completion: @escaping (Data?, URLResponse?, Error?) -> ()) {
           URLSession.shared.dataTask(with: url, completionHandler: completion).resume()
       }
    func getImage(for urlString: String, completion: @escaping (UIImage) -> () ) {
        guard let image = dict[urlString] else {
            downloadImage(from: urlString) { (image) in
                completion(image)
            }
            return
        }
        completion(image)
     }
    private func downloadImage(from str: String, completion: @escaping (UIImage) -> ()) {
            guard let url = URL(string: str) else { return  }
            getData(from: url) { data, response, error in
               guard let data = data, error == nil else { return }
                self.dict[str] = UIImage(data: data)
                completion(self.dict[str] ?? self.defaultImage)
           }
       }
    
}