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There are three things you generally want to do with Combine: publish values, manipulating those values, and receive those values elsewhere. Let's see how we can do each of those. Publishing Values Values are published with, predictably, Publishers. The most common way I see this happen is through @Published fields. So, for instance: class App… Continue reading Swift Combine: The Basics

Hello! Your company is probably remote now due to coronavirus/COVID-19. As a full time remote worker, I have some advice (and encouragement!). First, though, a caveat. If COVID-19 is causing your first experience with remote, understand that this isn’t normally how things go. This situation sucks, period. Even I'm not getting as much done, simply… Continue reading Coronemoting: Remote work during the coronavirus pandemic

My company owns a bunch of subway apps, but one of our most popular ones is SUBWAY:NYC. Obviously, this app in particular has seen dramatic decreases in usage as a result of the worldwide pandemic that's hit NYC especially hard. While that's bad for me, I thought it might be interesting to look at the… Continue reading When did New Yorkers start taking COVID-19 seriously? An analysis based on subway app usage

Caveat: I’m not the CDC. I’m just a former math professor who had a long flight last week and wanted to figure out the odds that someone on my plane had coronavirus. That said, the model I describe below is a reasonable approximation of the situation we're in for the time being; that is, unless… Continue reading Coronavirus: a mathematical prediction and what you can do about it

This is a cheat sheet for converting from ReactiveSwift to Combine. The origin of this document is me converting some of my libraries from one to the other, so they're just basic use cases of things I've used. As a result, this sheet by no means exhaustive, but is a good start and includes caveats… Continue reading ReactiveSwift to Combine Cheat Sheet

Generics are basically placeholders for types. They help you write specific code that can be used with (almost) any type. Suppose you're really tired of the whole if let dance. You want to write a function that will do that for you, so you can save some lines of code. Generics to the rescue! You could… Continue reading Quick iOS: Generics

Protocols allow you to define functions and properties that any class or struct which conforms to it must implement. This gives you the ability to rely only upon the things you need, while not putting too many restrictions on the conforming type. Let's look at an example. Consider the following: protocol Fireable { func fire()… Continue reading Quick iOS: Protocols

TLDR: calling a method on nil will crash. Variables that can be nil are called optional, and are defined using a question mark. To call a method on an optional variable, unwrap it by using a question mark (optional chaining), an exclamation point (force unwrapping), or an if let or guard let statement (conditional unwrapping).… Continue reading Quick iOS: Swift Optionals and nil

A client recently had me prepare a document containing suggestions on how to bring their app in line with current best practices as they continue to iterate and grow their team. Below I've listed some of those best practices, as I see them, and some suggestions on how to get there on a 'lazy' basis… Continue reading iOS App Codebase Best Practices

Want to be a one-person mobile app factory? Then you'll need the tools below! iOS Development Required This one is probably the most annoying if you're not already an Apple user: you'll need a Mac of some sort, first of all because Apple requires it, but secondly because only Macs can run Xcode, which iOS… Continue reading Mobile Dev Toolbox