Replace RxSwift View Model Types with Free Functions

Instead of writing view model types that expose the input and/or output ports as properties, consider writing free functions that are the transformation. This reminds me of Ken Scambler's proposal to get rid of test doubles through side-effect free function composition. One of his examples, simplified, goes like this: Instead of testing what customer.pay(amount, wallet) does in your tests by mocking the wallet object, you rewrite Wallet as a value object and change pay to return the effect.

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NSAppearance Change Notifications for Dark Mode and RxSwift Subscriptions

Last year, I had a full-time job from May until November and haven't had much time to prepare for Mojave. Then it hit hard, and I am still tweaking my apps to look properly in Mojave's Dark Mode. I welcome that macOS offers two modes now, .aqua and .darkAqua in programmer parlance. Because then I don't have to implement a homebrew solution in all my writing applications.

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RxSwift: Typing/Idle Event Stream for NSTextView

To improve my note editing app The Archive's responsiveness, I want to find out when the user is actively editing a note. Here's how to create the idle switch in RxSwift/RxCocoa. A simple enum of .typing and .idle will do for a start. Of course, NSTextViewDelegate provides a textDidChange(_:) callback to hook into; it's based on a notification, so you can also subscribe to the NSText.didChangeNotification directly if you don't want to use a delegate. That's the input signal I'm going to use.

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The 3 RxSwift Building Blocks of UI Components

So here's what I learned so far about the building blocks of reactive UI components from peeking at the RxCocoa source. UI components in general can have properties (read/write), input ports (read), and output ports (write). Classic UIKit/AppKit output ports would be delegate calls; classic input ports would be commands like display(banana:) that you probably write every day or so.

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