ReactiveSwift - Speaker Deck

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Teddy Ku January 27, 2017 ReactiveSwift

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What is • 2012: built for Github desktop app • Streams of values over time • Why? • ReactiveX: RxJava, Rx.NET • Reduce state, reduce bugs ReactiveCocoa

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• 2016: ReactiveCocoa split -> ReactiveSwift and ReactiveCocoa • Pure Swift rewrite • Type safety • Performance: didSet instead of What isReactiveSwift?

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• UITextFieldDelegate? • UITextFieldTextDidChange notiﬁcation? • textField.addTarget(self, action: #selector(textFieldDidChange),

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Too much state

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Signals = Events over time

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Less state, less bugs

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Signals

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EMAIL PASSWORD PASSWORD BUTTON ENABLED bind Signals

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T EMAIL PASSWORD PASSWORD BUTTON ENABLED [email protected] bind Signals

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T T EMAIL PASSWORD PASSWORD BUTTON ENABLED [email protected] bind *************** Signals

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T T T TTT EMAIL PASSWORD PASSWORD BUTTON ENABLED [email protected] bind *************** *************** Signals

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T T T TTT EMAIL PASSWORD PASSWORD BUTTON ENABLED F TTF [email protected] bind *************** *************** Signals

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T TTF T T TTT EMAIL PASSWORD PASSWORD BUTTON ENABLED F TTF T [email protected] bind *************** *************** Signals

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T TTF T T TTT EMAIL PASSWORD PASSWORD BUTTON ENABLED F TTF T T TTT [email protected] bind *************** *************** Signals

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T TTF T T TTT EMAIL PASSWORD PASSWORD BUTTON ENABLED F TTF T T TTT Translate to ReactiveSwift 1. Take latest string values 2. Check if each is not empty 3. Combine latest booleans 4. Return true if all not empty

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T TTF T T TTT EMAIL PASSWORD PASSWORD BUTTON ENABLED F TTF T T TTT |> is equivalent to Translate to ReactiveSwift 1. Take latest string values 2. Check if each is not empty 3. Combine latest booleans 4. Return true if all not empty

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Behavior is deﬁned linearly and concisely

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Live demo

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1. Take latest string values 2. Validate email and password 3. Validate passwords match 4. Combine all validation results 5. BUT: don’t show errors if all ﬁelds aren’t ﬁlled out yet Error Validation

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Live demo

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RxMarbles T TTF T T TTT EMAIL PASSWORD PASSWORD BUTTON ENABLED F TTF T T TTT HTTP://RXMARBLES.COM/#COMBINELATEST

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Recap • Less state, less bugs • Deﬁne behavior linearly & concisely • Types: Signal, Event https://github.com/tkuichooseyou/ReactiveSwiftTalk

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Bonus • Signals representing other async events • Network Requests • Loading from disk • Sockets - real time updates • Throttle • Retry • Cancel network requests