Blog by Jeevan

If you've written Swift for even a short time, you've already used Generics —whether you realized it or not. Types like Array , Dictionary , Set , and even Optional are all built using generics. Generics are one of Swift's most powerful language features because they help us write reusable, type-safe, and maintainable code . Let's understand them step by step. Why Do We Need Generics? Imagine writing separate functions for every data type. func printInt(_ value: Int) { ... } func printString(_ value: String) { ... } func printDouble(_ value: Double) { ... } The logic is identical, but we're repeating code simply because the data types are different. One option is to use Any . func printValue(_ value: Any) { print(value) } While this works, it comes with a drawback—you lose compile-time type safety and often need runtime type casting ( as? or as! ). Generics solve this problem by allowing us to write code once and reuse it with different data types without sacr...

When building an iOS app, it's important to organize your code in a way that keeps things clean, testable, and easy to maintain. One of the best ways to do that is by combining MVVM (Model–View–ViewModel) with Clean Architecture . 1. Presentation Layer — The SwiftUI Frontline This is where your app interacts with the user . In SwiftUI, the View and ViewModel live in this layer. View (SwiftUI View): These are your UI screens — for example, ContentView , LoginView , or ProfileView . SwiftUI Views are simple and reactive. They observe data and automatically update the UI when something changes. struct ContentView: View { @StateObject var viewModel = ContentViewModel() var body: some View { VStack { if viewModel.isLoading { ProgressView() } else { List(viewModel.items) { item in Text(item.title) } } } .onAppear { viewModel.fetchItems() } ...

Swift’s concurrency model introduced a cleaner and safer alternative to GCD. But with this came a common confusion: When should I use Task {} , Task.detached {} , and Task { @MainActor in ... } ? If you’ve ever wondered which one to pick, this article will clear it up with simple explanations and real-world guidance.

  When you start building apps in Swift or SwiftUI, you’ll often hear the term “Copy-on-Write” — or CoW for short. It sounds fancy, but the idea is actually very simple and smart. Let’s break it down. Swift uses value types like struct , Array , Dictionary , and String . Normally, when you copy a value type, you’d expect it to create a new copy in memory. But copying big data every time can be slow and wasteful. So Swift uses a trick called Copy-on-Write — it pretends to copy the data, but it doesn’t actually do it until you change something. var numbers = [1, 2, 3] var moreNumbers = numbers  // No real copy yet! moreNumbers.append(4)      // Now Swift makes a real copy here. At first, both variables share the same data. Only when you modify moreNumbers, Swift creates a separate copy so that the original numbers stays safe. This is how Swift gives you safe, independent data but still keeps things fast and memory-friendly. How It Connects to SwiftUI Now he...

If you’ve been building apps in Swift for a while, you’ve probably spent some time writing tests with  XCTest . It’s been the default testing framework on Apple platforms for years, and while it does the job, it often feels… a little clunky. Now enter Swift Testing — a newer, more modern testing framework that’s part of the Swift open-source project. The difference is immediately noticeable. Writing tests with Swift Testing feels like writing Swift code, not fighting a bunch of boilerplate. Here are some of the reasons why many developers are starting to prefer Swift Testing over XCTest: 1. The Syntax Just Flows Better In XCTest, you’re constantly reaching for XCTAssertEqual , XCTAssertTrue , XCTAssertNil , and so on. Each one has its own function, and you need to remember which is which. In Swift Testing, you simply use #expect with plain Swift expressions: #expect(result == 42) Compare that to: XCTAssertEqual(result, 42) Not a huge difference in one line, but when you multiply ...

 SwiftUI’s AsyncImage is handy, but every time your view appears, it refetches the image—leading to flicker, delays, and unnecessary network use. What if you could fetch once, then reuse instantly? That's exactly what the Cached Async Image  delivers: a memory-powered caching layer that keeps SwiftUI image loading smooth, snappy, and resilient. First a simple in-memory cache without disk persistence. This will be thread-safe and auto-purges under memory pressure. A Singleton wrapping NSCache for URL → UIImage caching as follows : final class ImageCache {   static let shared = ImageCache()   private init() {}   private let cache = NSCache<NSURL, UIImage>()   func image(for url: URL) -> UIImage? {     cache.object(forKey: url as NSURL)   }   func insertImage(_ image: UIImage?, for url: URL) {     guard let image else { return }     cache.setObject(image, forKey: url as NSURL)   }   func clearAll() { ...

Atomic Design is a methodology for creating design systems with a clear, consistent hierarchy. It was introduced by Brad Frost and is inspired by chemistry. The core idea is to break down UI components into the smallest possible parts (atoms) and compose them to build more complex components and pages. Atomic Design Hierarchy 1. Atoms 
The basic building blocks of UI — buttons, labels, text fields, icons, colors, spacing units.
Example: PrimaryButton, AppText, Icon 2. Molecules 
 Groupings of atoms that form simple components.
Example: SearchBar = TextField + Icon, LabeledSwitch 3. Organisms 
 Relatively complex, standalone components made of atoms and molecules.
Example: LoginForm, UserCard, HeaderView 4. Templates 
 Layouts or skeletons that define the structure of pages using organisms.
Example: AuthScreenTemplate, DashboardTemplate 5. Pages 
 Final screens with real data/content, composed of templates.
Example: LoginScreen, SettingsScreen. Here is how an example folders structure l...

SwiftUI empowers developers with powerful APIs to design user interfaces, making it easier than ever to create visually stunning screens that enhance the user experience (UX). Once these screens are crafted, the next step is to seamlessly connect them using navigation tools like NavigationView or NavigationStack . But here’s the catch: navigation logic can quickly spiral into a tangled mess as your app scales with more features and screens. The challenge lies in writing a clean, maintainable routing layer that keeps your codebase organized and easy to extend. To tackle this, adopting a dedicated routing layer is essential, especially when working with structured app architectures like VIPER or MVVM. In VIPER, routing plays a pivotal role as the "R" in the acronym. In MVVM, however, routing often takes a backseat in SwiftUI projects. This article introduces a simple yet effective approach to integrate a routing layer within SwiftUI, ensuring your app’s navigation logic rem...

UIImage comes with property " renderingMode " from iOS 7 onwards. It can be set either 'alwaysTemplate' or 'alwaysOriginal'. This enum property helps us to re-use images that may thin your app size too. Let's get into to a real scenario ! I have added button as heart icon that gives like or dislike functionality for a picture. As you can see in the result below, heart image turns red when liked and stays gray when disliked. In such cases only one image asset can be used. Considering a UIButton object already created and added as a subview in the project, let's start with functionality. Again, I have only one image with name 'heart' in the asset folder (with gray fill). Using same image, I can create 2 instances of UIImage objects using rendering modes.     let notLikedImage = UIImage . init (named: "heart" )?. withRenderingMode (. alwaysOriginal )  let likedImage = UIImage . init (named: "heart" )?....

Recently, I started with a Card view added as a subview of UIView in a view-controller. When a view controller created along subviews, it tends to use entire screen bounds and also slips behind Tab bar or Navigation bar. In my current situation, it's second case. Casually new iOS developers will write a patch by additional value for coordinate y and subtracting bar height from its size. A lot of them posted in SO threads too : How to prevent UINavigationBar from covering top of view? View got hidden below UINavigationBar iOS 7 Navigation Bar covers some part of view at Top So, how I got solved ? self.edgesForExtendedLayout = [] This  will avoid all subviews in a view controller get behind any bars. Read full apple  documentation on here. Full Source code below :  //Simple view controller where its view layed-out as a card. class WidgetCardViewController : UIViewController { var containerView = UIView () //MARK:- View Controller Life Cyc...

Recently I published a countdown app .  At one point of development - I have to show a timer on a UILabel which ticks on each seconds. As usual I started  setting text to a label object - self .timerLabel.text = someString Easy piece of cake right !?   But wait ... it won't take much user attention when timer ticks on every seconds. So I decided to make use of a simple animation while label gets text update. I found there are dozens of ways to animate a label. In this short article, I listed 3 best way you can animate text on a label. ( Spoiler Alert 👀- I decided to go with 3rd option)  1. Fade In - Fade out animation : CATransition class has got transition type `fade`. With timing function of CATransition - I was able to see the below result. let animation: CATransition = CATransition () animation.timingFunction = CAMediaTimingFunction (name: CAMediaTimingFunctionName .easeInEaseOut) animation.type = CATransitionType .fade animation.subtype = C...