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() } ...

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 ...

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...

 Here's a quick reference list with some common abbreviations that I have came across frequently in my Engineering journey :  1. PR – Pull Request A request submitted by a developer to merge their code changes from one branch to another, typically for review and collaboration before integration. 2. MR – Merge Request Similar to a Pull Request, a Merge Request is used in GitLab to request code merging. It includes review, discussion, and approval before finalizing changes. 3. CR – Change Request A formal proposal to modify a system or product, often triggered by stakeholder feedback, bug reports, or evolving requirements. 4. LADR – Lightweight Architectural Decision Record A brief document that captures an important architectural decision made during a project. 5. BRD – Business Requirement Document Outlines the high-level business needs, objectives, and expectations of a project. It's used as a reference for aligning technical development with business goals. 6. LLD – Low...

Sorting is a fundamental operation in computer science and Understanding the basic sorting algorithms is essential for both interviews and real-world programming tasks. I am sharing the notes that I have taken in my learning curve. 1. Selection Sort Selection Sort repeatedly finds the minimum element from the unsorted part and puts it at the beginning. Steps: Loop through the array. For each index, find the smallest element in the rest of the array. Swap it with the current index. Time Complexity: O(n²) Example: [29, 10, 14, 37, 13] → [10, 29, 14, 37, 13] → [10, 13, 14, 37, 29] → [10, 13, 14, 37, 29] → [10, 13, 14, 29, 37] 2. Insertion Sort Insertion Sort builds the sorted array one element at a time by inserting each element into its correct position. Steps: Start from index 1. Compare current element with the left-side elements. Shift elements to the right and insert at the correct position. Time Complexity: O(n²) Example: [8, 4, 1, 3] → [4, 8, 1, 3] → [1, 4, 8, 3] → [1, 3, 4, 8] 3. ...

Installation steps of cocoapods in the new Macs with M1 chipset is little different than Intel based Macs. If we casually run `pod install`, we are likely to encounter error related to the ffi gem 🤨. Open the terminal and follow below steps to solve the error and install pod dependencies successfully. Step1 : At first, install ffi gem intel version > sudo arch -x86_64 gem install ffi Steps 2: Install cocoapod  > sudo gem install cocoapods Steps 3 (optional) : Go to project root folder and initialise pod file if not created already. > arch -x86_64 pod init Steps 4: Now Install pod dependencies. > arch -x86_64 pod install

Given two kangaroos on a number line ready to jump in the positive direction, we have to figure out a way to get both kangaroos at the same location at the same time as part of the show. If it is possible, return YES , otherwise return NO . Read full problem statement from here Working solution in Swift           func kangaroo ( x1 : Int , v1 : Int , x2 : Int , v2 : Int ) -> String {         var multiplier = 1         // 1.         while (multiplier < 10000 ) {             // 2.             if (x1+(v1*multiplier) == x2+(v2*multiplier)) {                 return "YES"             }                          multiplier += 1         }            ...

 In this post we can see complete solution for the HackerRank Exercise Subarray Division. The problem statement goes like this - Determine how many ways can divide the chocolate bar (as contiguous segment) between Lily and Ron given condition :  The length of the segment matches Ron's birth month The sum of the integers on the squares is equal to his birth day. Read complete challenge detail from HackerRank Working solution in Swift given below:      func birthday ( s : [ Int ] , d : Int , m : Int ) -> Int { var sCount = 0 var index = 0 // 1 while ( index < s. count ) { var dayLength = 0 let limit = index +m > s. count ? s. count : index +m // 2 for jIndex in index ..< limit { dayLength += s [ jIndex ] } // 3 if dayLength == d { sCount += 1 } ...

 In this post we can solve exercise problem "Apple and Orange" in which we should print the number of apples and oranges that land on Sam's house.  Read complete challenge detail from  hackerrank.com Full Swift Solution is given below: func countApplesAndOranges ( s : Int , t : Int , a : Int , b : Int , apples : [ Int ] , oranges : [ Int ]) -> Void { // 1 let applesDistance = apples. map ( { $ 0 + a }) var totalAppleOk = 0 applesDistance. forEach ({ ad in // 2 if ( s .. . t ) . contains ( ad ) { totalAppleOk = totalAppleOk + 1 } }) print ( " \( totalAppleOk ) " ) // prints number of Apples let orangeDistance = oranges. map ( { $ 0 + b }) var totalOrangeOk = 0 orangeDistance. forEach ({ od in if ( s .. . t ) . contains ( od ) { totalOrangeOk = totalOrangeOk ...

In this post, we have Swift 5.0 solution for Hackerrank exercise - Utopian Tree . We have find out the height of  Utopian Tree, which goes through 2 cycles of growth every year. Each spring, it doubles in height. Each summer, its height increases by 1 meter. Full details of exercise link  hackerrank.com/challenges/utopian-tree/problem Here is the working solution:           func   utopianTree ( n :   Int )   ->   Int   {          var   height   =   0          for   cycle   in   0 .. . n   {              height   =   ( cycle   -   1 )   %   2   ==   0   ?   height   *   2   :   height   +   1            }  ...

I enjoyed using Web Inspector tool from Safari Developer options to debug active web pages in iPhone or iPad. For instance, WKWebView running on iPhone. With the update of MacOS Big Sur 11.4 it got broke !! The Safari (14.1.1) web inspector only limited to Sources, Console and Audit. Also this issue started floating in SO thread here . Last week I got rescued by a lesser known application (at lest in my team!) Safari Technology Preview from Apple. Safari Technology Preview app will give you full scale options includes the most recent version of WebKit, the rendering engine that powers Safari. It requires a Mac running macOS Mojave v10.14 or later. I highly recommend this Apple provided in-house Browser for Developer.

I would like to share all possible channels & resources that helps to pitch in iOS development. I'm sure existing iOS ninjas who are already consuming those in one or other ways. Before listing my points - we all know it's most important to keep updated techs and trends. Many cases I have seen some of the channels & connections helped developers to get their new jobs or app contracts. 1. Apple's Official Developer guide. Apple Documentation  is the first go over for all references.  Swift.org for Swift Language starting point. WWDC Videos (& New app launched as well) 2. Social Media Groups - Fast & easy way to connect with iOS community. Facebook Group   Twitter Lists for iOS handles 3. Slack workspaces - A sweet hub of all iOS developers connected by channels. ios-developers.slack.com (Suggested) 4. Online Courses   - Gives opportunity to learn and be certified developers. Udemy AppBrewery  Alison ( and more ) 5...

We commonly use Collection view where its cell size calculated run time. The flow layout delegate is responsible to return individual cell sizes. BUT in most of the cases, delegate method `collectionView: layout sizeForItem:` expects cell size too early. Before generating actual cell size. extension YourViewController : UICollectionViewDelegateFlowLayout { func collectionView ( _ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize { return CGSize (width: externalWidth, height: externalHeight) } } For instance, if a cell size depends on external view and its frame is not yet ready - results with wrong (or outdated) cell size. Typically happens for the first time view controller laid out all views. You can find similar queries in StackOverflow community : Collection view sizeForItemNotWorking UICollectionViewCell content wrong size on first load How to refresh UICollec...