Generic URLSession call

fetchObject.swift

// Generic function to fetch and decode JSON into a Codable object
func fetchDecodedObject<T: Codable>(from urlString: String, completion: @escaping (Result<T, NetworkError>) -> Void) {
    // Step 1: Create a URL instance
    guard let url = URL(string: urlString) else {
        completion(.failure(.badURL))
        return
    }
    
    // Step 2: Create a URLSession
    let session = URLSession.shared
    
    // Step 3: Create a URLSessionDataTask
    let task = session.dataTask(with: url) { (data, response, error) in
        // Step 4: Handle the Data, Response, and Error
        if let error = error {
            completion(.failure(.requestFailed(error)))
            return
        }
        
        guard let httpResponse = response as? HTTPURLResponse, httpResponse.statusCode == 200 else {
            completion(.failure(.badStatusCode((response as? HTTPURLResponse)?.statusCode ?? -1)))
            return
        }
        
        guard let data = data else {
            completion(.failure(.requestFailed(error!)))
            return
        }
        
        // Decode the JSON data into the generic type T
        do {
            let decodedObject = try JSONDecoder().decode(T.self, from: data)
            completion(.success(decodedObject))
        } catch let decodingError {
            completion(.failure(.decodingFailed(decodingError)))
        }
    }
    
    // Start the task
    task.resume()
}

sample.swift

struct MyModel: Codable {
    var property1: String
    var property2: Int
    // ... other properties
}

enum NetworkError: Error {
    case badURL
    case requestFailed(Error)
    case badStatusCode(Int)
    case decodingFailed(Error)
}

fetchDecodedObject(from: "https://api.example.com/endpoint") { (result: Result<MyModel, NetworkError>) in
    switch result {
    case .success(let model):
        print(model)
    case .failure(let error):
        print("Error: \(error)")
    }
}