Combine examples

Other Projects/GitHub Search/GitHubSearchWithSwiftUI/View/RepositoryListViewModel.swift

@@ -11,39 +11,60 @@ import Foundation
 import SwiftUI
 
 final class RepositoryListViewModel: BindableObject {
+    typealias SearchRepositories = (String) -> AnyPublisher<Result<[Repository], ErrorResponse>, Never>
 
     let didChange: AnyPublisher<RepositoryListViewModel, Never>
     private let _didChange = PassthroughSubject<RepositoryListViewModel, Never>()
 
     private let _searchWithQuery = PassthroughSubject<String, Never>()
-    private lazy var repositoriesAssign = Subscribers.Assign(object: self, keyPath: \.repositories)
+    private var cancellables: [AnyCancellable] = []
 
     private(set) var repositories: [Repository] = [] {
         didSet {
-            // TODO: Do not want to use DispatchQueue.main here
-            DispatchQueue.main.async {
-                self._didChange.send(self)
-            }
+            _didChange.send(self)
         }
     }
-
-    deinit {
-        repositoriesAssign.cancel()
+    private(set) var errorMessage: String? {
+        didSet {
+            _didChange.send(self)
+        }
     }
+    var text: String = ""
+
+    init<S: Scheduler>(searchRepositories: @escaping SearchRepositories = RepositoryAPI.search,
+                       mainScheduler: S) {
 
-    init() {
         self.didChange = _didChange.eraseToAnyPublisher()
 
-        _searchWithQuery
-            .flatMap { query -> AnyPublisher<[Repository], Never> in
-                RepositoryAPI.search(query: query)
-                    .replaceError(with: [])
+        let response = _searchWithQuery
+            .filter { !$0.isEmpty }
+            .debounce(for: .milliseconds(300), scheduler: mainScheduler)
+            .flatMapLatest { query -> AnyPublisher<([Repository], String?), Never> in
+                searchRepositories(query)
+                    .map { result -> ([Repository], String?) in
+                        switch result {
+                        case let .success(repositories):
+                            return (repositories, nil)
+                        case let .failure(response):
+                            return ([], response.message)
+                        }
+                    }
                     .eraseToAnyPublisher()
             }
-            .receive(subscriber: repositoriesAssign)
+            .receive(on: mainScheduler)
+            .share()
+
+        cancellables += [
+            response
+                .map { $0.0 }
+                .assign(to: \.repositories, on: self),
+            response
+                .map { $0.1 }
+                .assign(to: \.errorMessage, on: self)
+        ]
     }
 
-    func search(query: String) {
-        _searchWithQuery.send(query)
+    func search() {
+        _searchWithQuery.send(text)
     }
 }