WWDC19

Table of Contents

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• Table of Contents
• Combine in Practice - Thursday * @Published * currentValuePublisher() * passThroughPublisher() * eraseToAnyPublisher * debounce * removeDuplicates * sink() & assign()

Combine in Practice - Thursday

Session materials: https://developer.apple.com/videos/play/wwdc2019/721/

This is an example oriented heavy code focused session. Please follow the session materials.

• Combine has a built in bakc-pressure compared to RxSwift!
• It doesn’t have disposeBags and the allocation is handled automatically
  • There is also a built-in cancel mechanism to terminate an ongoing emmission

@Published

• A new property wrapper to turn properties into publishers at the same time
  • Similar to Variable<T> or BehaviorRelay<T> on RxSwift ``` @Published var foo: String self.foo = 1 let boo = self.foo // Immediately assigns the current value as 1

foo.sink() { // subscription stream will get 1 and 2 }

self.foo = “2”

```

currentValuePublisher()

• Holds the last emitted value as BehaviorSubject or similar to ReplaySubject in RxSwift

  passThroughPublisher()

• Acts like a bridge from non rx world to rx world. (Similar to publishSubject in RxSwift)

  eraseToAnyPublisher

• casts a given chain into a publisher to be used again across the API

  debounce

• debounces the emission and can schedule on a given thread

  removeDuplicates

• distinctUntilChanged() on Rx

• There are more than 90 common Rx operators built into Combine!

sink() & assign()

• subscribe() & bind() on RxSwift to get the emitted value on a subscriber