100 Days of SwiftUI

Today I started the 100 Days of SwiftUI course by Paul Hudson. I've been wanting to learn iOS development for a while now, and I think this is a brilliant opportunity to do so. I'm excited to see what I can build with it.

This post will be updated as I progress through the course. I will be adding the new things I learn and the projects I build as I go along. I will try not to skip any days, but we will see how it goes.

So far, all my experience with Swift is limited to this Frontend Masters tutorial by Maximiliano Firtman. So, I have some basic knowledge of the language and the framework, but I'm still a beginner.

In addition to this post, my progress can be followed on:

• Mastodon (updates and thoughts)
• Github (code)

Day 1: Variables, constants, strings, and numbers

Today, I reviewed some basic concepts of Swift. I already knew about variables and constants, but I learned a couple of new things as well. For example, I learned about multi-line strings ("""), type safety (1 + 2.0 = error), and a couple of useful methods (uppercased(), hasPrefix(), isMultiple(of:)). Of course, the first day was an easy one, but nevertheless, it was a good refresher.

Day 2: Booleans, string interpolation, and checkpoint 1

This day's material covered such topics as booleans and string interpolation. I noticed that the interpolation syntax in Swift is more elegant and a bit more powerful 🤔 than in Javascript, so that's interesting. At the end of the lesson, I finished the first checkpoint assignment - converting temperature from °C to °F (classic).

Day 3: Arrays, dictionaries, sets, and enums

Day 3 had a surprisingly large amount of new information. I learned a couple of previously unknown concepts, such as dictionaries, sets, and enums. I believe that each of them might have particular use cases, but I'm not sure yet when to use them in practice. I suppose it will become clear in the nearest feature.

So far, it seems that the first two weeks of the course will be directed towards learning/refreshing the basics of Swift as a language. After that, we will start using SwiftUI and building something more tangible. I hope that, at this point, the process will become more practical.

Day 4: Type annotations and checkpoint 2

Today's lesson was brief, yet it covered an important topic - type annotations. From my point of view, in Swift, it works exactly the same way as in Typescript. I am not 100% sure about type inference, so I will check it later.

The second checkpoint assignment was about returning unique values from the array by converting it to a set. It also seems like a task that can be accomplished almost the same way in Javascript or Typescript.

As you can see from today's image, I still use VSCode for Swift development. I am not sure if it's the best option, and I will probably switch to Xcode sooner or later.

Day 5: If, switch, and the ternary operator

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Day 6: Loops, summary, and checkpoint 3

I accidentally skipped a day yesterday, so I am catching up today with two sections. The first (Day 5) was about conditionals - if, switch and the ternary operator (2 > 1 ? "Yes" : "No"). Once again, it feels pretty much the same as in Javascript, except for some minor differences - Int and Double can not be compared directly in Swift, and switch statements must be exhaustive, i.e., go through all the cases or have a default case.

Day 6 was dedicated to loops - for and while. I learned about ignoring the value (_), excluding the last entry (..<), generating a random number (Int.random(in: 1...10)), and using break and continue statements to control the flow of the loop.

The third checkpoint contained a FizzBuzz task, which I solved at first by using the % operator. Then, I realized that Swift has a .isMultiple(of:) method and refactored the code to use it.

Day 7: Functions, parameters, and return values

It is a wrap for the first week of the course. Today's lesson was an introduction to functions in Swift. I learned the basic syntax, as well as some handy tricks, such as omitting the return keyword for single-expression functions, using external parameter names, and skipping the parameter label with _.

Day 8: Default values, throwing functions, and checkpoint 4

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Day 9: Closures, passing functions into functions, and checkpoint 5

Days 8 and 9 were all about functions and closures. These parts were packed with new information, and I learned a lot of new things, though I am unsure if I remember all of them. Especially the part about closures felt a bit tricky, and I will probably need to revisit it later. However, it feels like a powerful feature, so I also used it in the latest checkpoint assignment to chain a couple of functions together - let formattedNumbers = luckyNumbers.filter {$0 % 2 != 0}.sorted {$0 < $1}.map {"\($0) is a lucky number"}.

Day 10: Structs, computed properties, and property observers

Day 10 was an introduction to structs. It was a pretty new concept for me, but it seems clear so far. I learned about structs' methods (and mutating keyword), computed properties (getters and setters), and property observers (willSet and didSet). The last part about custom initializers was somewhat confusing, but I think I got the main idea.

Original post @ create-react-app.com

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