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Peter Friese | Developer Advocate, Firebase Charlo!e Liang | So"ware Engineer, Firebase  + Firebase for Apple Developers @charlo!eCLiang @pete#riese

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Architecture Swi!UI 2 Life Cycle Firebase Firestore Authentication Combine async/await Completion block WidgetKit

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Architecture For Data-Driven Apps Photo by Lance Anderson on Unsplash

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#one-book-a-week-challenge

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Drill-down navigation Three-column layout (iPad / Mac) Single source of truth Driving factors UI always in sync

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UI always in sync

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BookShelfView BookEditView BookDetailsView BookRowView Source of Truth books: [Book] @ObservableObject @Binding Book Book Book

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Challenge #1 This needs to be a binding But this isn’t a list of bindings

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struct BookShelfView: View { @Binding var bookShelf: BookShelf var body: some View { List { ForEach(Array(bookShelf.books.enumerated()), id: \.element.id) { index, item in BookRowView(book: $bookShelf.books[index]) } .onDelete { indexSet in bookShelf.books.remove(atOffsets: indexSet) } } .navigationTitle(bookShelf.title) } } Solution #1: iterate over enumerated items !

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struct BookShelfView: View { @Binding var bookShelf: BookShelf var body: some View { List { ForEach($bookShelf.books) { $book in BookRowView(book: $book) } .onDelete { indexSet in bookShelf.books.remove(atOffsets: indexSet) } } .navigationTitle(bookShelf.title) } } Solution #1: use list bindings Everything is now bindable

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Learn more h"ps://pete#riese.dev/swi!ui-list-item-bindings-behind-the-scenes/

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How to update only when the user commits? Challenge #2

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struct BookEditView: View { @Binding var book: Book @ObservedObject var bookEditViewModel: BookEditViewModel init(book: Binding) { self._book = book self.bookEditViewModel = BookEditViewModel(book: book.wrappedValue) } var body: some View { TextField("Book title", text: $bookEditViewModel.book.title) } func save() { self.book = bookEditViewModel.book dismiss() } } Solution 2: use inner @ObservableObject

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struct BookEditView: View { @Binding var book: Book @ObservedObject var bookEditViewModel: BookEditViewModel init(book: Binding) { self._book = book self.bookEditViewModel = BookEditViewModel(book: book.wrappedValue) } var body: some View { TextField("Book title", text: $bookEditViewModel.book.title) } func save() { self.book = bookEditViewModel.book dismiss() } } Solution 2: use inner @ObservableObject

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struct BookEditView: View { @Binding var book: Book @ObservedObject var bookEditViewModel: BookEditViewModel init(book: Binding) { self._book = book self.bookEditViewModel = BookEditViewModel(book: book.wrappedValue) } var body: some View { TextField("Book title", text: $bookEditViewModel.book.title) } func save() { self.book = bookEditViewModel.book dismiss() } } Solution 2: use inner @ObservableObject

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struct BookEditView: View { @Binding var book: Book @ObservedObject var bookEditViewModel: BookEditViewModel init(book: Binding) { self._book = book self.bookEditViewModel = BookEditViewModel(book: book.wrappedValue) } var body: some View { TextField("Book title", text: $bookEditViewModel.book.title) } func save() { self.book = bookEditViewModel.book dismiss() } } Solution 2: use inner @ObservableObject

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Solution 2

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class BookEditViewModel: ObservableObject { @Published var book: Book @Published var isISBNValid: Bool = true init(book: Book) { self.book = book self.$book .map { checkISBN(isbn: $0.isbn) } .assign(to: &$isISBNValid) } } Solution 2: use inner @ObservableObject Bonus: use Combine to perform validation

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Learn more about Building SwiftUI Components h"ps://www.youtube.com/c/pete#riese

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Architecture Swi!UI 2 Life Cycle Firebase Firestore Authentication Combine async/await Completion block WidgetKit

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Run with confidence Engage users Develop apps faster

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Run with confidence Crashlytics Performance Monitoring Test Lab App Distribution Engage users Analytics Predictions Cloud Messaging Remote Config A/B Testing Dynamic Links In-app Messaging Develop apps faster Auth Cloud Functions Cloud Firestore Hosting ML Kit Realtime Database Cloud Storage bit.ly/what-is-firebase Extensions Machine Learning

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#protip: Put it beneath Asset.xcasset

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Don’t forget to add to all the targets!

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Swift Package Manager now officially supported! h"ps://github.com/%rebase/%rebase-ios-sdk

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!

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Application Lifecycle SwiftUI 2 Photo by Thor Alvis on Unsplash

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SwiftUI 2: No more AppDelegate! import SwiftUI @main struct BookShelfApp: App { @StateObject var store = BookShelfStore(shelves: BookShelf.samples) var body: some Scene { WindowGroup { NavigationView { BookShelvesView(store: store) Text("Select a shelf to see its books") Text("Select a book to see its details") } } } }

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SwiftUI 2: No more AppDelegate! import SwiftUI @main struct BookShelfApp: App { @StateObject var store = BookShelfStore(shelves: BookShelf.samples) var body: some Scene { WindowGroup { NavigationView { BookShelvesView(store: store) Text("Select a shelf to see its books") Text("Select a book to see its details") } } } }

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Solution 1: use initialiser import SwiftUI @main struct BookShelfApp: App { @StateObject var store = BookShelfStore(shelves: BookShelf.samples) var body: some Scene { WindowGroup { NavigationView { BookShelvesView(store: store) Text("Select a shelf to see its books") Text("Select a book to see its details") }

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Solution 1: use initialiser import SwiftUI @main struct BookShelfApp: App { @StateObject var store = BookShelfStore(shelves: BookShelf.samples) var body: some Scene { WindowGroup { NavigationView { BookShelvesView(store: store) Text("Select a shelf to see its books") Text("Select a book to see its details") } init() { FirebaseApp.configure() }

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Solution 2: use UIApplicationDelegateAdaptor import SwiftUI import Firebase class AppDelegate: NSObject, UIApplicationDelegate { func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) !" Bool { FirebaseApp.configure() return true } } @main struct BookShelfApp: App { @UIApplicationDelegateAdaptor(AppDelegate.self) var delegate

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Solution 2: use UIApplicationDelegateAdaptor import SwiftUI import Firebase class AppDelegate: NSObject, UIApplicationDelegate { func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) !" Bool { FirebaseApp.configure() return true } } @main struct BookShelfApp: App { @UIApplicationDelegateAdaptor(AppDelegate.self) var delegate

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Solution 2: use UIApplicationDelegateAdaptor import SwiftUI import Firebase class AppDelegate: NSObject, UIApplicationDelegate { func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) !" Bool { FirebaseApp.configure() return true } } @main struct BookShelfApp: App { @UIApplicationDelegateAdaptor(AppDelegate.self) var delegate

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Solution 2: use UIApplicationDelegateAdaptor import SwiftUI import Firebase class AppDelegate: NSObject, UIApplicationDelegate { func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) !" Bool { FirebaseApp.configure() return true } } @main struct BookShelfApp: App { @UIApplicationDelegateAdaptor(AppDelegate.self) var delegate

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Watch the scene phase Handle deep links Continue user activities Do more with the new life cycle

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Watch the scene phase Handle deep links Continue user activities Learn more pete#riese.dev/ultimate-guide-to-swi!ui2-application-lifecycle/

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Architecture Swi!UI 2 Life Cycle Firebase Firestore Authentication Combine async/await Completion block WidgetKit

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Firestore

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One-Time Fetches Offline Mode Effortless Syncing

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bird_type: airspeed: coconut_capacity: isNative: icon: vector: distances_traveled: "swallow" 42.733 0.62 false { x: 36.4255, y: 25.1442, z: 18.8816 } [42, 39, 12, 42] Document

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Collection Sub-Collection

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Top level collections “books” collection a single book document

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struct Book: Identifiable { var id = String? var shelfId: String? var userId: String? var title: String var author: String var isbn: String var pages: Int var isRead: Bool = false var coverEditionKey: String? } Data Model

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func fetchBook(documentId: String) { let docRef = Firestore.firestore().collection("books").document(documentId) docRef.getDocument { document, error in if let error = error as NSError? { print("Error getting document: \(error.localizedDescription)") } else { if let document = document { let id = document.documentID let data = document.data() let title = data?["title"] as? String !# "" let numberOfPages = data?["numberOfPages"] as? Int !# 0 let author = data?["author"] as? String !# "" self.book = Book(id:id, title: title, numberOfPages: numberOfPages, author: author) } } } } Fetching a document from Firestore

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func fetchBook(documentId: String) { let docRef = Firestore.firestore().collection("books").document(documentId) docRef.getDocument { document, error in if let error = error as NSError? { print("Error getting document: \(error.localizedDescription)") } else { if let document = document { let id = document.documentID let data = document.data() let title = data?["title"] as? String !# "" let numberOfPages = data?["numberOfPages"] as? Int !# 0 let author = data?["author"] as? String !# "" self.book = Book(id:id, title: title, numberOfPages: numberOfPages, author: author) } } } } Fetching a document from Firestore

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func fetchBook(documentId: String) { let docRef = Firestore.firestore().collection("books").document(documentId) docRef.getDocument { document, error in if let error = error as NSError? { print("Error getting document: \(error.localizedDescription)") } else { if let document = document { let id = document.documentID let data = document.data() let title = data?["title"] as? String !# "" let numberOfPages = data?["numberOfPages"] as? Int !# 0 let author = data?["author"] as? String !# "" self.book = Book(id:id, title: title, numberOfPages: numberOfPages, author: author) } } } } Fetching a document from Firestore

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func fetchBook(documentId: String) { let docRef = Firestore.firestore().collection("books").document(documentId) docRef.getDocument { document, error in if let error = error as NSError? { print("Error getting document: \(error.localizedDescription)") } else { if let document = document { let id = document.documentID let data = document.data() let title = data?["title"] as? String !# "" let numberOfPages = data?["numberOfPages"] as? Int !# 0 let author = data?["author"] as? String !# "" self.book = Book(id:id, title: title, numberOfPages: numberOfPages, author: author) } } } } Fetching a document from Firestore

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func fetchBook(documentId: String) { let docRef = Firestore.firestore().collection("books").document(documentId) docRef.getDocument { document, error in if let error = error as NSError? { print("Error getting document: \(error.localizedDescription)") } else { if let document = document { let id = document.documentID let data = document.data() let title = data?["title"] as? String !# "" let numberOfPages = data?["numberOfPages"] as? Int !# 0 let author = data?["author"] as? String !# "" self.book = Book(id:id, title: title, numberOfPages: numberOfPages, author: author) } } } } Fetching a document from Firestore

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func fetchBook(documentId: String) { let docRef = Firestore.firestore().collection("books").document(documentId) docRef.getDocument { document, error in if let error = error as NSError? { print("Error getting document: \(error.localizedDescription)") } else { if let document = document { let id = document.documentID let data = document.data() let title = data?["title"] as? String !# "" let numberOfPages = data?["numberOfPages"] as? Int !# 0 let author = data?["author"] as? String !# "" self.book = Book(id:id, title: title, numberOfPages: numberOfPages, author: author) } } } } Fetching a document from Firestore

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func fetchBook(documentId: String) { let docRef = Firestore.firestore().collection("books").document(documentId) docRef.getDocument { document, error in if let error = error as NSError? { print("Error getting document: \(error.localizedDescription)") } else { if let document = document { let id = document.documentID let data = document.data() let title = data?["title"] as? String !# "" let numberOfPages = data?["numberOfPages"] as? Int !# 0 let author = data?["author"] as? String !# "" self.book = Book(id:id, title: title, numberOfPages: numberOfPages, author: author) } } } } Fetching a document from Firestore if let document = document { let id = document.documentID let data = document.data() let title = data?["title"] as? String !# "" let numberOfPages = data?["numberOfPages"] as? Int !# 0 let author = data?["author"] as? String !# "" self.book = Book(id:id, title: title, numberOfPages: numberOfPages, author: author) } Can we do better?

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(Yes, we can)

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func fetchBook(documentId: String) { let docRef = Firestore.firestore().collection("books").document(documentId) docRef.getDocument { document, error in if let error = error as NSError? { print("Error getting document: \(error.localizedDescription)") } else { if let document = document { let id = document.documentID let data = document.data() let title = data?["title"] as? String !# "" let numberOfPages = data?["numberOfPages"] as? Int !# 0 let author = data?["author"] as? String !# "" self.book = Book(id:id, title: title, numberOfPages: numberOfPages, author: author) } } } } Fetching a document from Firestore

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func fetchBook(documentId: String) { let docRef = Firestore.firestore().collection("books").document(documentId) docRef.getDocument { document, error in if let error = error as NSError? { print("Error getting document: \(error.localizedDescription)") } else { } } } Mapping data using Codable if let document = document { do { self.book = try document.data(as: Book.self) } catch { print(error) } }

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func fetchBook(documentId: String) { let docRef = Firestore.firestore().collection("books").document(documentId) docRef.getDocument { document, error in if let error = error as NSError? { print("Error getting document: \(error.localizedDescription)") } else { } } } Mapping data using Codable if let document = document { do { self.book = try document.data(as: Book.self) } catch { print(error) } }

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BookShelfView BookEditView BookDetailsView BookRowView Source of Truth books: [Book] @ObservableObject @Binding Book Book Book Review: Architecture

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BookShelfView BookDetailsView BookRowView Source of Truth books: [Book] @ObservableObject @Binding Book Book Review: Architecture Snapshot Listener

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class BookStore: ObservableObject { var db = Firestore.firestore() private var listenerRegistration: ListenerRegistration? @Published var books = [Book]() func subscribe() { listenerRegistration = db.collection("books") .addSnapshotListener { [weak self] (querySnapshot, error) in guard let documents = querySnapshot!$documents else { return } self!$books = documents.compactMap { queryDocumentSnapshot in let result = Result { try queryDocumentSnapshot.data(as: Book.self) } switch result { case .success(let book): if let book = book { return book Fetching a collection of documents

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class BookStore: ObservableObject { var db = Firestore.firestore() private var listenerRegistration: ListenerRegistration? @Published var books = [Book]() func subscribe() { listenerRegistration = db.collection("books") .addSnapshotListener { [weak self] (querySnapshot, error) in guard let documents = querySnapshot!$documents else { return } self!$books = documents.compactMap { queryDocumentSnapshot in let result = Result { try queryDocumentSnapshot.data(as: Book.self) } switch result { case .success(let book): if let book = book { return book Fetching a collection of documents

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class BookStore: ObservableObject { var db = Firestore.firestore() private var listenerRegistration: ListenerRegistration? @Published var books = [Book]() func subscribe() { listenerRegistration = db.collection("books") .addSnapshotListener { [weak self] (querySnapshot, error) in guard let documents = querySnapshot!$documents else { return } self!$books = documents.compactMap { queryDocumentSnapshot in let result = Result { try queryDocumentSnapshot.data(as: Book.self) } switch result { case .success(let book): if let book = book { return book Fetching a collection of documents

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class BookStore: ObservableObject { var db = Firestore.firestore() private var listenerRegistration: ListenerRegistration? @Published var books = [Book]() func subscribe() { listenerRegistration = db.collection("books") .addSnapshotListener { [weak self] (querySnapshot, error) in guard let documents = querySnapshot!$documents else { return } self!$books = documents.compactMap { queryDocumentSnapshot in let result = Result { try queryDocumentSnapshot.data(as: Book.self) } switch result { case .success(let book): if let book = book { return book Fetching a collection of documents

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class BookStore: ObservableObject { var db = Firestore.firestore() private var listenerRegistration: ListenerRegistration? @Published var books = [Book]() func subscribe() { listenerRegistration = db.collection("books") .addSnapshotListener { [weak self] (querySnapshot, error) in guard let documents = querySnapshot!$documents else { return } self!$books = documents.compactMap { queryDocumentSnapshot in let result = Result { try queryDocumentSnapshot.data(as: Book.self) } switch result { case .success(let book): if let book = book { return book Fetching a collection of documents

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class BookStore: ObservableObject { var db = Firestore.firestore() private var listenerRegistration: ListenerRegistration? @Published var books = [Book]() func subscribe() { listenerRegistration = db.collection("books") .addSnapshotListener { [weak self] (querySnapshot, error) in guard let documents = querySnapshot!$documents else { return } self!$books = documents.compactMap { queryDocumentSnapshot in let result = Result { try queryDocumentSnapshot.data(as: Book.self) } switch result { case .success(let book): if let book = book { return book Fetching a collection of documents

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class BookStore: ObservableObject { var db = Firestore.firestore() private var listenerRegistration: ListenerRegistration? @Published var books = [Book]() func subscribe() { listenerRegistration = db.collection("books") .addSnapshotListener { [weak self] (querySnapshot, error) in guard let documents = querySnapshot!$documents else { return } self!$books = documents.compactMap { queryDocumentSnapshot in let result = Result { try queryDocumentSnapshot.data(as: Book.self) } switch result { case .success(let book): if let book = book { return book Fetching a collection of documents

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Learn more h"ps://pete#riese.dev/%restore-codable-the-comprehensive-guide/

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import Foundation import Combine import Firebase import FirebaseFirestoreSwift import os class BookStore: ObservableObject { !% MARK: - Dependencies var db = Firestore.firestore() !% MARK: - Publishers @Published var user: User? @Published var books = [Book]() !% MARK: - Private attributes @Published private var userId: String = "unknown" private var listenerRegistration: ListenerRegistration? private var cancellables = Set() Fetching a collection of documents

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!% A Book value could not be initialized from the DocumentSnapshot. switch error { case DecodingError.typeMismatch(_, let context): self!$logger.debug("\(error.localizedDescription): \ (context.debugDescription)") case DecodingError.valueNotFound(_, let context): self!$logger.debug("\(error.localizedDescription): \ (context.debugDescription)") case DecodingError.keyNotFound(_, let context): self!$logger.debug("\(error.localizedDescription): \ (context.debugDescription)") case DecodingError.dataCorrupted(let key): self!$logger.debug("\(error.localizedDescription): \ (key.debugDescription)") default: self!$logger.debug("Error decoding document: \ (error.localizedDescription)") } return nil } } } } Fetching a collection of documents

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!% A Book value could not be initialized from the DocumentSnapshot. switch error { case DecodingError.typeMismatch(_, let context): self!$logger.debug("\(error.localizedDescription): \ (context.debugDescription)") case DecodingError.valueNotFound(_, let context): self!$logger.debug("\(error.localizedDescription): \ (context.debugDescription)") case DecodingError.keyNotFound(_, let context): self!$logger.debug("\(error.localizedDescription): \ (context.debugDescription)") case DecodingError.dataCorrupted(let key): self!$logger.debug("\(error.localizedDescription): \ (key.debugDescription)") default: self!$logger.debug("Error decoding document: \ (error.localizedDescription)") } return nil } } } } Fetching a collection of documents about 100 lines of code

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struct BookShelfView: View { @FirestoreQuery( collectionPath: "books", predicates: [ .where("userId", isEqualTo: userId), ] ) var books: Result<[Book], Error> @State var userId = "F18EBA5E" var body: some View { List(books) { book in Text(book.title) } } } Firestore Property Wrapper Firebase 8.9.0 @FloWritesCode @mo&enditlevsen Thanks to

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Architecture Swi!UI 2 Life Cycle Firebase Firestore Authentication Combine async/await Completion block WidgetKit

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Driving User Engagement Photo by ROBIN WORRALL on Unsplash

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Driving User Engagement Noti%cations Share Extensions WidgetKit

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Notification Service Extension Noti%cation Service Extension + Firebase Messaging Be!er visualisation of noti%cations Available in watchOS as well

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Watch the scene phase Handle deep links Continue user activities Learn more h"ps://%rebase.blog/posts/2019/09/fcm-image-noti%cation

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Firebase + WidgetKit Mini travel blog How to initialise Firebase How to access Firebase services

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Post Image ShareExtension Widget iOS App Architecture

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class ShareViewController: SLComposeServiceViewController { override func didSelectPost() { !" get data from share controller context Task { !" write image data to Cloud Storage let _ = try await ref.putDataAsync(self.imageData as Data) let url = try await ref.downloadURL() !" write post data to Firestore let post = Post(description: description !# "", url: url.absoluteString) try db.collection("Posts").document("post").setData(from: post) !" refresh widgets and return to share controller WidgetCenter.shared.reloadAllTimelines() extensionContext!$completeRequest(returningItems: []) } } Firebase in a ShareViewController

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class ShareViewController: SLComposeServiceViewController { override func didSelectPost() { !" get data from share controller context Task { !" write image data to Cloud Storage let _ = try await ref.putDataAsync(self.imageData as Data) let url = try await ref.downloadURL() !" write post data to Firestore let post = Post(description: description !# "", url: url.absoluteString) try db.collection("Posts").document("post").setData(from: post) !" refresh widgets and return to share controller WidgetCenter.shared.reloadAllTimelines() extensionContext!$completeRequest(returningItems: []) } } Firebase in a ShareViewController

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class ShareViewController: SLComposeServiceViewController { override func didSelectPost() { !" get data from share controller context Task { !" write image data to Cloud Storage let _ = try await ref.putDataAsync(self.imageData as Data) let url = try await ref.downloadURL() !" write post data to Firestore let post = Post(description: description !# "", url: url.absoluteString) try db.collection("Posts").document("post").setData(from: post) !" refresh widgets and return to share controller WidgetCenter.shared.reloadAllTimelines() extensionContext!$completeRequest(returningItems: []) } } Firebase in a ShareViewController

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class ShareViewController: SLComposeServiceViewController { override func didSelectPost() { !" get data from share controller context Task { !" write image data to Cloud Storage let _ = try await ref.putDataAsync(self.imageData as Data) let url = try await ref.downloadURL() !" write post data to Firestore let post = Post(description: description !# "", url: url.absoluteString) try db.collection("Posts").document("post").setData(from: post) !" refresh widgets and return to share controller WidgetCenter.shared.reloadAllTimelines() extensionContext!$completeRequest(returningItems: []) } } Firebase in a ShareViewController

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class ShareViewController: SLComposeServiceViewController { override func didSelectPost() { !" get data from share controller context Task { !" write image data to Cloud Storage let _ = try await ref.putDataAsync(self.imageData as Data) let url = try await ref.downloadURL() !" write post data to Firestore let post = Post(description: description !# "", url: url.absoluteString) try db.collection("Posts").document("post").setData(from: post) !" refresh widgets and return to share controller WidgetCenter.shared.reloadAllTimelines() extensionContext!$completeRequest(returningItems: []) } } Firebase in a ShareViewController

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class ShareViewController: SLComposeServiceViewController { override func didSelectPost() { !" get data from share controller context Task { !" write image data to Cloud Storage let _ = try await ref.putDataAsync(self.imageData as Data) let url = try await ref.downloadURL() !" write post data to Firestore let post = Post(description: description !# "", url: url.absoluteString) try db.collection("Posts").document("post").setData(from: post) !" refresh widgets and return to share controller WidgetCenter.shared.reloadAllTimelines() extensionContext!$completeRequest(returningItems: []) } } Firebase in a ShareViewController

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Post Image ShareExtension Widget iOS App Architecture Post Image

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func getTimeline(for configuration: ConfigurationIntent, in context: Context, completion: @escaping (Timeline) !" Void) { if FirebaseApp.app() !& nil { FirebaseApp.configure() } Task { let (image, text) = try await PostRepository.getPost(imageName: “image.png") let entry = SimpleEntry( date: Calendar.current.date(byAdding: .minute, value: 15, to: Date())!, configuration: configuration, image: image, text: text ) let timeline = Timeline(entries: [entry], policy: .atEnd) completion(timeline) } } Firebase in a Widget

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func getTimeline(for configuration: ConfigurationIntent, in context: Context, completion: @escaping (Timeline) !" Void) { if FirebaseApp.app() !& nil { FirebaseApp.configure() } Task { let (image, text) = try await PostRepository.getPost(imageName: “image.png") let entry = SimpleEntry( date: Calendar.current.date(byAdding: .minute, value: 15, to: Date())!, configuration: configuration, image: image, text: text ) let timeline = Timeline(entries: [entry], policy: .atEnd) completion(timeline) } } Firebase in a Widget

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func getTimeline(for configuration: ConfigurationIntent, in context: Context, completion: @escaping (Timeline) !" Void) { if FirebaseApp.app() !& nil { FirebaseApp.configure() } Task { let (image, text) = try await PostRepository.getPost(imageName: “image.png") let entry = SimpleEntry( date: Calendar.current.date(byAdding: .minute, value: 15, to: Date())!, configuration: configuration, image: image, text: text ) let timeline = Timeline(entries: [entry], policy: .atEnd) completion(timeline) } } Firebase in a Widget

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func getTimeline(for configuration: ConfigurationIntent, in context: Context, completion: @escaping (Timeline) !" Void) { if FirebaseApp.app() !& nil { FirebaseApp.configure() } Task { let (image, text) = try await PostRepository.getPost(imageName: “image.png") let entry = SimpleEntry( date: Calendar.current.date(byAdding: .minute, value: 15, to: Date())!, configuration: configuration, image: image, text: text ) let timeline = Timeline(entries: [entry], policy: .atEnd) completion(timeline) } } Firebase in a Widget

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func getTimeline(for configuration: ConfigurationIntent, in context: Context, completion: @escaping (Timeline) !" Void) { if FirebaseApp.app() !& nil { FirebaseApp.configure() } Task { let (image, text) = try await PostRepository.getPost(imageName: “image.png") let entry = SimpleEntry( date: Calendar.current.date(byAdding: .minute, value: 15, to: Date())!, configuration: configuration, image: image, text: text ) let timeline = Timeline(entries: [entry], policy: .atEnd) completion(timeline) } } Firebase in a Widget

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import FirebaseStorage import FirebaseStorageSwift import FirebaseFirestore import FirebaseFirestoreSwift struct PostRepository { static func getPost(imageName: String) async throws !" (UIImage, String) { let ref = Storage.storage().reference().child(imageName) let data = try await ref.data(maxSize: 20 * 1024 * 2048) let image = UIImage(data: data)! let db = Firestore.firestore() let docRef = db.collection("Posts").document("post") let document = try await docRef.getDocument() let post = try document.data(as: Post.self) return (image, post.description) Firebase in a Widget

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import FirebaseStorage import FirebaseStorageSwift import FirebaseFirestore import FirebaseFirestoreSwift struct PostRepository { static func getPost(imageName: String) async throws !" (UIImage, String) { let ref = Storage.storage().reference().child(imageName) let data = try await ref.data(maxSize: 20 * 1024 * 2048) let image = UIImage(data: data)! let db = Firestore.firestore() let docRef = db.collection("Posts").document("post") let document = try await docRef.getDocument() let post = try document.data(as: Post.self) return (image, post.description) Firebase in a Widget

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import FirebaseStorage import FirebaseStorageSwift import FirebaseFirestore import FirebaseFirestoreSwift struct PostRepository { static func getPost(imageName: String) async throws !" (UIImage, String) { let ref = Storage.storage().reference().child(imageName) let data = try await ref.data(maxSize: 20 * 1024 * 2048) let image = UIImage(data: data)! let db = Firestore.firestore() let docRef = db.collection("Posts").document("post") let document = try await docRef.getDocument() let post = try document.data(as: Post.self) return (image, post.description) Firebase in a Widget

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import FirebaseStorage import FirebaseStorageSwift import FirebaseFirestore import FirebaseFirestoreSwift struct PostRepository { static func getPost(imageName: String) async throws !" (UIImage, String) { let ref = Storage.storage().reference().child(imageName) let data = try await ref.data(maxSize: 20 * 1024 * 2048) let image = UIImage(data: data)! let db = Firestore.firestore() let docRef = db.collection("Posts").document("post") let document = try await docRef.getDocument() let post = try document.data(as: Post.self) return (image, post.description) Firebase in a Widget

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Architecture Swi!UI 2 Life Cycle Firebase Firestore Authentication Combine async/await Completion block WidgetKit

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Authentication Photo by Conve&Kit on Unsplash

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Authentication Photo by Eduardo Soares on Unsplash

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Authentication Photo by Victor Freitas on Unsplash

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

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Sign in the user Update the data model Secure users’ data How to implement Firebase Authentication?

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Anonymous Authentication “Guest” accounts, rather

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func signIn() { registerStateListener() if Auth.auth().currentUser !& nil { Auth.auth().signInAnonymously() } } Anonymous Authentication

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No content

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SignInWithAppleButton( onRequest: { !!' }, onCompletion: { result in !!' let appleIDToken = appleIDCredential.identityToken let idTokenString = String(data: appleIDToken, encoding: .utf8) let credential = OAuthProvider.credential(withProviderID: “apple.com", idToken: idTokenString, rawNonce: nonce) Auth.auth().signIn(with: credential) { (authResult, error) in if (error !( nil) { !!' } print(“User signed in") dismiss() } } ).frame(width: 280, height: 45, alignment: .center) Sign in with Apple

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SignInWithAppleButton( onRequest: { !!' }, onCompletion: { result in !!' let appleIDToken = appleIDCredential.identityToken let idTokenString = String(data: appleIDToken, encoding: .utf8) let credential = OAuthProvider.credential(withProviderID: “apple.com", idToken: idTokenString, rawNonce: nonce) Auth.auth().signIn(with: credential) { (authResult, error) in if (error !( nil) { !!' } print(“User signed in") dismiss() } } ).frame(width: 280, height: 45, alignment: .center) Sign in with Apple

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SignInWithAppleButton( onRequest: { !!' }, onCompletion: { result in !!' let appleIDToken = appleIDCredential.identityToken let idTokenString = String(data: appleIDToken, encoding: .utf8) let credential = OAuthProvider.credential(withProviderID: “apple.com", idToken: idTokenString, rawNonce: nonce) Auth.auth().signIn(with: credential) { (authResult, error) in if (error !( nil) { !!' } print(“User signed in") dismiss() } } ).frame(width: 280, height: 45, alignment: .center) Sign in with Apple

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SignInWithAppleButton( onRequest: { !!' }, onCompletion: { result in !!' let appleIDToken = appleIDCredential.identityToken let idTokenString = String(data: appleIDToken, encoding: .utf8) let credential = OAuthProvider.credential(withProviderID: “apple.com", idToken: idTokenString, rawNonce: nonce) Auth.auth().signIn(with: credential) { (authResult, error) in if (error !( nil) { !!' } print(“User signed in") dismiss() } } ).frame(width: 280, height: 45, alignment: .center) Sign in with Apple

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SignInWithAppleButton( onRequest: { !!' }, onCompletion: { result in !!' let appleIDToken = appleIDCredential.identityToken let idTokenString = String(data: appleIDToken, encoding: .utf8) let credential = OAuthProvider.credential(withProviderID: “apple.com", idToken: idTokenString, rawNonce: nonce) Auth.auth().signIn(with: credential) { (authResult, error) in if (error !( nil) { !!' } print(“User signed in") dismiss() } } ).frame(width: 280, height: 45, alignment: .center) Sign in with Apple Firebase SDK

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SignInWithAppleButton( onRequest: { !!' }, onCompletion: { result in !!' let appleIDToken = appleIDCredential.identityToken let idTokenString = String(data: appleIDToken, encoding: .utf8) let credential = OAuthProvider.credential(withProviderID: “apple.com", idToken: idTokenString, rawNonce: nonce) Auth.auth().signIn(with: credential) { (authResult, error) in if (error !( nil) { !!' } print(“User signed in") dismiss() } } ).frame(width: 280, height: 45, alignment: .center) Sign in with Apple Firebase SDK

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All books are stored in one single collection Which user do they belong to?

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let query = db.collection("books") .whereField("userId", isEqualTo: self.userId) query .addSnapshotListener { [weak self] (querySnapsho guard let documents = querySnapshot!$documents els Signed in user

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rules_version = '2'; service cloud.firestore { match /databases/{database}/documents { match /{document=**} { allow create: if request.auth !( null; allow read, update, delete: if request.auth !( null !) resource.data.userId !& request.auth.uid; } } } Security Rules Only signed-in users can create new documents Only owners may read and modify a document

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Architecture Swi!UI 2 Life Cycle Firebase Firestore Authentication Combine async/await Completion block WidgetKit

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Combine

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auth!$signInAnonymously() let user = auth!$currentUser print("User signed in with user ID: \(user!$uid)") This might be nil

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auth!$signInAnonymously() let user = auth!$currentUser print("User signed in with user ID: \(user!$uid)") auth!$signInAnonymously { result, error in guard let result = result else { return } print("User signed in with user ID: \(result.user.uid)") } Do this instead

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auth!$signInAnonymously() let user = auth!$currentUser print("User signed in with user ID: \(user!$uid)") auth!$signInAnonymously { result, error in guard let result = result else { return } print("User signed in with user ID: \(result.user.uid)") } @Published var user: User? !!' auth!$signInAnonymously() .map{ $0.user } .replaceError(with: nil) .assign(to: &$user) Even better

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Launched with Firebase 8.9.0 h"ps://github.com/%rebase/%rebase-ios-sdk/projects/3

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Architecture Swi!UI 2 Life Cycle Firebase Firestore Authentication Combine async/await Completion block WidgetKit

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async/await Photo by Stephen H on Unsplash

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extension ArticleAnalyser { func process(url: String, completion: @escaping (Article) !" Void) { self.fetchArticle(from: url) { result in switch result { case .failure(let error): print(error.localizedDescription) case .success(let html): self.extractTitle(from: html) { result in switch result { case .failure(let error): print(error.localizedDescription) case .success(let title): self.extractText(from: html) { result in switch result { case .failure(let error): print(error.localizedDescription) case .success(let text): self.extractImage(from: url) { result in Problem: Callback Pyramid of Doom

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extension AsyncArticleAnalyser { func process(url: String) async throws !" Article { let htmlText = try await fetchArticle(from: url) let text = try await extractText(from: htmlText) let title = try await extractTitle(from: htmlText) let imageUrl = try await extractImage(from: url) let tags = await inferTags(from: text) return Article(url: url, title: title, tags: tags, imageUrlString: imageUrl) } } Solution: Use async/await Swift 5.5

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func fetchArticle(from url: String) async throws !" String { guard let url = URL(string: url) else { throw AnalyserError.badURL } return try await withUnsafeThrowingContinuation { continuation in URLSession.shared.downloadTask(with: url) { (localUrl, urlResponse, error) in guard let localUrl = localUrl else { continuation.resume(throwing: AnalyserError.badURL) return } if let htmlText = try? String(contentsOf: localUrl) { continuation.resume(returning: htmlText) } } .resume() } } Solution: Use async/await Swift 5.5

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func fetchArticle(from url: String) async throws !" String { guard let url = URL(string: url) else { throw AnalyserError.badURL } return try await withUnsafeThrowingContinuation { continuation in URLSession.shared.downloadTask(with: url) { (localUrl, urlResponse, error) in guard let localUrl = localUrl else { continuation.resume(throwing: AnalyserError.badURL) return } if let htmlText = try? String(contentsOf: localUrl) { continuation.resume(returning: htmlText) } } .resume() } } Solution: Use async/await Swift 5.5

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func fetchArticle(from url: String) async throws !" String { guard let url = URL(string: url) else { throw AnalyserError.badURL } return try await withUnsafeThrowingContinuation { continuation in URLSession.shared.downloadTask(with: url) { (localUrl, urlResponse, error) in guard let localUrl = localUrl else { continuation.resume(throwing: AnalyserError.badURL) return } if let htmlText = try? String(contentsOf: localUrl) { continuation.resume(returning: htmlText) } } .resume() } } Solution: Use async/await Swift 5.5

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func fetchArticle(from url: String) async throws !" String { guard let url = URL(string: url) else { throw AnalyserError.badURL } return try await withUnsafeThrowingContinuation { continuation in URLSession.shared.downloadTask(with: url) { (localUrl, urlResponse, error) in guard let localUrl = localUrl else { continuation.resume(throwing: AnalyserError.badURL) return } if let htmlText = try? String(contentsOf: localUrl) { continuation.resume(returning: htmlText) } } .resume() } } Solution: Use async/await Swift 5.5

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auth!$signInAnonymously { result, error in guard let result = result else { return } print("User signed in with user ID: \(result.user.uid)") } do { let result = try await Auth.auth().signIn(withEmail: email, password: password) print("User signed in with user ID: \(result.user.uid)") } catch { print(error) } Works with Firebase, too! Callback-style

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Learn more h"ps://pete#riese.dev/async-await-in-swi! h"ps://www.youtube.com/watch?v=sEKw2BMcQtQ

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Architecture Swi!UI 2 Life Cycle Firebase Firestore Authentication Combine async/await Completion block WidgetKit

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Architecture Swi!UI 2 Life Cycle Firebase Firestore Authentication Combine async/await Completion block WidgetKit

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Register now - it’s free! h"ps://io.google/2022/ Google I/O 2022

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Thanks! @pete#riese h"ps://github.com/pete#riese/BookShelf Code @charlo"eCLiang

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Credits %nish by Megan Chown from the Noun Project Time by Nikita Kozin from the Noun Project pipe by Komkrit Noenpoempisut from the Noun Project Passpo& by ProSymbols from the Noun Project spiral by Alexander Skowalsky from the Noun Project Architecture by Ervin Bolat from the Noun Project Firebase logos cou&esy h"ps://%rebase.google.com/brand-guidelines Firebase logos cou&esy h"ps://%rebase.google.com/brand-guidelines Thanks! Hea& by Roman from the Noun Project Dashboard by BomSymbols from the Noun Project

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The End.