AsyncNinja/AsyncNinja

A complete set of primitives for concurrency and reactive programming on Swift

[[Gitter]](https://gitter.im/AsyncNinja/Lobby) [[CocoaPods]](https://cocoapods.org/pods/AsyncNinja) [[Carthage compatible]](https://github.com/Carthage/Carthage) [[Build Status]](https://travis-ci.org/AsyncNinja)

1.4.0 is the latest and greatest, but only for Swift 4.2 and 5.0
use 1.3.0 is for Swift 4.0+
use 1.2.4 for latest release for Swift 3

| | Features | |---|---| | 🦄 powerful primitives | Future, Promise, Channel, Producer, Sink, Cache, ... | | 🤘 versatile transformations | map, filter, recover, debounce, distinct, ... | | ✌️ convenient combination | flatMap, merge, zip, sample, scan, reduce, ... | | 🙌 improves existing things | Key-Value Observing, target-action, notifications, bindings | | 🍳 less boilerplate code | neat cancellation, threading, memory manament | | 🕶 extendable | powerful extensions for URLSession, UI controls, CoreData, ... | | 🍱 all platforms | 🖥 macOS 10.10+ 📱 iOS 8.0+ 📺 tvOS 9.0+ ⌚️ watchOS 2.0+ 🐧 Linux | | 🤓 documentation | 100% + sample code, see full documentation | | 🔩 simple integration | SPM, CocoaPods, Carthage |

* Moving to nice asynchronous Swift code: GitHub, Medium

Known users

Communication

Reactive Programming

reactive properties

let searchResults = searchBar.rp.text
  .debounce(interval: 0.3)
  .distinct()
  .flatMap(behavior: .keepLatestTransform) { (query) -> Future<[SearchResult]> in
    return query.isEmpty
      ? .just([])
      : searchGitHub(query: query).recover([])
  }

bindings

unbinds automatically
dispatches to a correct queue automatically
no .observeOn(MainScheduler.instance) and .disposed(by: disposeBag)

class MyViewController: UIViewController {
  /* ... */
  @IBOutlet weak var myLabel: UILabel!

  override func viewDidLoad() {
    super.viewDidLoad()
    UIDevice.current.rp.orientation
      .map { $0.description }
      .bind(myLabel.rp.text)
  }
  
  /* ... */
}

contexts usage

no [weak self]
no DispatchQueue.main.async { ... }
no .observeOn(MainScheduler.instance)

class MyViewController: NSViewController {
  let service: MyService

  /* ... */
  
  func fetchAndPresentItems(for request: Request) {
    service.perform(request: request)
      .map(context: self, executor: .primary) { (self, response) in
        return self.items(from: response)
      }
      .onSuccess(context: self) { (self, items) in
        self.present(items: items)
      }
      .onFailure(context: self) { (self, error) in
        self.present(error: error)
      }
  }
  
  func items(from response: Response) throws -> [Items] {
    /* ... extract items from response ... */
  }
  
  func present(items: [Items]) {
    /* ... update UI ... */
  }
}

class MyService {
  func perform(request: Request) -> Future<Response> {
    /* ... */
  }
}

In Depth

Let's assume that we have:

Person is an example of a struct that contains information about the person.
MyService is an example of a class that serves as an entry point to the model. Works in a background.
MyViewController is an example of a class that manages UI-related instances. Works on the main queue.

Code on callbacks

extension MyViewController {
  func present(personWithID identifier: String) {
    myService.fetch(personWithID: identifier) {
      (person, error) in

      /* do not forget to dispatch to the main queue */
      DispatchQueue.main.async {

        /* do not forget the [weak self] */
        [weak self] in
        guard let strongSelf = self
          else { return }

        if let person = person {
          strongSelf.present(person: person)
        } else if let error = error {
          strongSelf.present(error: error)
        } else {
          fatalError("There is neither person nor error. What has happened to this world?")
        }
      }
    }
  }
}

extension MyService {
  func fetch(personWithID: String, callback: @escaping (Person?, Error?) -> Void) {
    /* ... */
  }
}

"do not forget" comment x2
the block will be retained and called even if MyViewController was already deallocated

Code with other libraries that provide futures

extension MyViewController {
  func present(personWithID identifier: String) {
    myService.fetch(personWithID: identifier)

      /* do not forget to dispatch to the main queue */
      .onComplete(executor: .main) {

        /* do not forget the [weak self] */
        [weak self] (completion) in
        if let strongSelf = self {
          completion.onSuccess(strongSelf.present(person:))
          completion.onFailure(strongSelf.present(error:))
        }
      }
  }
}

extension MyService {
  func fetch(personWithID: String) -> Future<Person> {
    /* ... */
  }
}

"do not forget" comment x2
the block will be retained and called even if MyViewController was already deallocated

Code with AsyncNinja

extension MyViewController {
  func present(personWithID identifier: String) {
    myService.fetch(personWithID: identifier)
      .onSuccess(context: self) { (self, person) in
        self.present(person: person)
      }
      .onFailure(context: self) { (self, error) in
        self.present(error: error)
      }
  }
}

extension MyService {
  func fetch(personWithID: String) -> Future<Person> {
    /* ... */
  }
}

"do not forget" comment NONE
the block will be retained and called as long as specified context (MyViewController) exists
Want to see extended explanation?

Using Futures

Let's assume that we have function that finds all prime numbers lesser than n

func primeNumbers(to n: Int) -> [Int] { /* ... */ }

Making future

let futurePrimeNumbers: Future<[Int]> = future { primeNumbers(to: 10_000_000) }

Applying transformation

let futureSquaredPrimeNumbers = futurePrimeNumbers
  .map { (primeNumbers) -> [Int] in
    return primeNumbers.map { (number) -> Int
      return number * number
    }
  }

Synchronously waiting for completion

if let fallibleNumbers = futurePrimeNumbers.wait(seconds: 1.0) {
  print("Number of prime numbers is \(fallibleNumbers.success?.count)")
} else {
  print("Did not calculate prime numbers yet")
}

Subscribing for completion

futurePrimeNumbers.onComplete { (falliblePrimeNumbers) in
  print("Number of prime numbers is \(falliblePrimeNumbers.success?.count)")
}

Combining futures

let futureA: Future<A> = /* ... */
let futureB: Future<B> = /* ... */
let futureC: Future<C> = /* ... */
let futureABC: Future<(A, B, C)> = zip(futureA, futureB, futureC)

Transition from callbacks-based flow to futures-based flow:

class MyService {
  /* implementation */
  
  func fetchPerson(withID personID: Person.Identifier) -> Future<Person> {
    let promise = Promise<Person>()
    self.fetchPerson(withID: personID, callback: promise.complete)
    return promise
  }
}

Transition from futures-based flow to callbacks-based flow

class MyService {
  /* implementation */
  
  func fetchPerson(withID personID: Person.Identifier,
                   callback: @escaping (Fallible<Person>) -> Void) {
    self.fetchPerson(withID: personID)
      .onComplete(callback)
  }
}

Using Channels

Let's assume we have function that returns channel of prime numbers: sends prime numbers as finds them and sends number of found numbers as completion

func makeChannelOfPrimeNumbers(to n: Int) -> Channel<Int, Int> { /* ... */ }

Applying transformation

let channelOfSquaredPrimeNumbers = channelOfPrimeNumbers
  .map { (number) -> Int in
      return number * number
    }

Synchronously iterating over update values.

for number in channelOfPrimeNumbers {
  print(number)
}

Synchronously waiting for completion

if let fallibleNumberOfPrimes = channelOfPrimeNumbers.wait(seconds: 1.0) {
  print("Number of prime numbers is \(fallibleNumberOfPrimes.success)")
} else {
  print("Did not calculate prime numbers yet")
}

Synchronously waiting for completion #2

let (primeNumbers, numberOfPrimeNumbers) = channelOfPrimeNumbers.waitForAll()

Subscribing for update

channelOfPrimeNumbers.onUpdate { print("Update: \($0)") }

Subscribing for completion

channelOfPrimeNumbers.onComplete { print("Completed: \($0)") }

Making `Channel`

func makeChannelOfPrimeNumbers(to n: Int) -> Channel<Int, Int> {
  return channel { (update) -> Int in
    var numberOfPrimeNumbers = 0
    var isPrime = Array(repeating: true, count: n)

    for number in 2..<n where isPrime[number] {
      numberOfPrimeNumbers += 1
      update(number)

      // updating seive
      var seiveNumber = number + number
      while seiveNumber < n {
        isPrime[seiveNumber] = false
        seiveNumber += number
      }
    }

    return numberOfPrimeNumbers
  }
}

Package Metadata

Repository: AsyncNinja/AsyncNinja

Homepage: https://async.ninja/

Stars: 157

Forks: 16

Open issues: 1

Default branch: master

Primary language: swift

License: MIT

Topics: async, channel, concurrency, concurrency-library, functional, future, reactive, swift

README: README.md

AsyncNinja/AsyncNinja

A complete set of primitives for concurrency and reactive programming on Swift

Communication

Reactive Programming

reactive properties

bindings

contexts usage

In Depth

Code on callbacks

Code with other libraries that provide futures

Code with AsyncNinja

Using Futures

Making future

Applying transformation

Synchronously waiting for completion

Subscribing for completion

Combining futures

Transition from callbacks-based flow to futures-based flow:

Transition from futures-based flow to callbacks-based flow

Using Channels

Applying transformation

Synchronously iterating over update values.

Synchronously waiting for completion

Synchronously waiting for completion #2

Subscribing for update

Subscribing for completion

Making Channel

Package Metadata

Making `Channel`