Combine examples

Other Projects/GitHub Search/GitHubSearchWithSwiftUI/Extension/Publisher.Extension.swift

@@ -0,0 +1,36 @@
+//
+//  Publisher.Extension.swift
+//  GitHubSearchWithSwiftUI
+//
+//  Created by John Holdsworth on 09/07/2019.
+//  Copyright © 2019 jp.marty-suzuki. All rights reserved.
+//
+
+import Combine
+
+extension Publisher {
+
+    /// - seealso: https://twitter.com/peres/status/1136132104020881408
+    func flatMapLatest<T: Publisher>(_ transform: @escaping (Self.Output) -> T) -> Publishers.SwitchToLatest<T, Publishers.Map<Self, T>> where T.Failure == Self.Failure {
+        map(transform).switchToLatest()
+    }
+}
+
+extension Publisher {
+
+    static func empty() -> AnyPublisher<Output, Failure> {
+        return Publishers.Empty()
+            .eraseToAnyPublisher()
+    }
+
+    static func just(_ output: Output) -> AnyPublisher<Output, Failure> {
+        return Just(output)
+            .catch { _ in AnyPublisher<Output, Failure>.empty() }
+            .eraseToAnyPublisher()
+    }
+
+    static func fail(_ error: Failure) -> AnyPublisher<Output, Failure> {
+        return Publishers.Fail(error: error)
+            .eraseToAnyPublisher()
+    }
+}

Other Projects/GitHub Search/GitHubSearchWithSwiftUI/Extension/URLSession.Combine.swift

@@ -15,44 +15,26 @@ extension CombineExtension where Base == URLSession {
 
     func send(request: URLRequest) -> AnyPublisher<Data, URLSessionError> {
 
-        AnyPublisher<Data, URLSessionError> { [base] subscriber in
-
-            let task = base.dataTask(with: request) { data, response, error in
-
+        base.dataTaskPublisher(for: request)
+            .mapError { URLSessionError.urlError($0) }
+            .flatMap { data, response -> AnyPublisher<Data, URLSessionError> in
                 guard let response = response as? HTTPURLResponse else {
-                    subscriber.receive(completion: .failure(.invalidResponse))
-                    return
+                    return .fail(.invalidResponse)
                 }
 
                 guard 200..<300 ~= response.statusCode else {
-                    let e = URLSessionError.serverError(statusCode: response.statusCode,
-                                                        error: error)
-                    subscriber.receive(completion: .failure(e))
-                    return
+                    return .fail(.serverErrorMessage(statusCode: response.statusCode,
+                                                     data: data))
                 }
 
-                guard let data = data else {
-                    subscriber.receive(completion: .failure(.noData))
-                    return
-                }
-
-                if let error = error {
-                    subscriber.receive(completion: .failure(.unknown(error)))
-                } else {
-                    _ = subscriber.receive(data)
-                    subscriber.receive(completion: .finished)
-                }
+                return .just(data)
             }
-
-            // TODO: cancel task when subscriber cancelled
-            task.resume()
-        }
+            .eraseToAnyPublisher()
     }
 }
 
 enum URLSessionError: Error {
     case invalidResponse
-    case noData
-    case serverError(statusCode: Int, error: Error?)
-    case unknown(Error)
+    case serverErrorMessage(statusCode: Int, data: Data)
+    case urlError(URLError)
 }