Swift & SwiftUI Interview Prep – Senior iOS Developers


Here are some of the key questions that came up:

1. What are PassThroughSubject and CurrentValueSubject?
2. Explain Publisher and Subscriber.
3. Difference between @State and @Binding in SwiftUI.
4. What is AnyPublisher?
5. When do we use eraseToAnyPublisher?
6. What is AnyView?
7. What does the @Published property wrapper do?
8. Write a Combine pipeline to fetch data from two different network requests and output only when both complete. (💻 Live Coding Test)
9. What is a Cancellable?
10.Types of operators in Combine.
11. Usage of sink with completion.
12. Explain switchToLatest.
13. Build a 2-screen SwiftUI app (list + detail) that makes an API call using Combine only. (⏱️ 20-min Live Coding Test)
14. Difference between onReceive and onChange modifiers.
15. Coding Exercise:
👉 Given an array of strings, transform it into a new array:
Input → ["a", "b", "c"]
Output → ["c-0", "b-1", "a-2"]
⚡️ Requirement: Solve this using Swift higher-order functions such as map, enumerated, etc.

💡 If you’re preparing for iOS interviews, these are excellent questions to sharpen your fundamentals and practical skills in SwiftUI + Combine.

🤝 What other Swift / SwiftUI interview questions have you faced recently? Let’s share and learn together!

Comments

Post a Comment

Popular posts from this blog

Steps to follow to submitting iPhone/iPad Apps To The Apple App Store

Step 1: Certificate is an essential element to submit or test an application on iPhone. It comes with code sign(Signatures) which would verified when an application is submitted on apple store or when tested on iPhone. One can bypass these if an application is installed on jail-break iPhone or  when submitted on Cydia but this is not possible when one wants submit it to AppStore. One has to through 2 step procedure to create a certificate from developer portal. I copied those two from “iPhone developer portal”  Generating Certificate Signing Request  Submitting a Certificate Signing Request for Approval Generating a Certificate Signing Request :   Open the Utilities folder and launch Key chain Access from the Applications folder.  Set the value of Online Certificate Status Protocol (OCSP) and Certificate Revocation List (CRL) to “off” in the Preferences Menu.  Select Key chain Access -> Certificate Assistant -> Request a Certif...
Read more

what is appDelegate?

Image
The  AppDelegate  is sort of like the entry point for your application.  It implements  UIApplicationDelegate  and contains methods that are called when your application launches, when is going to the background (i.e. when you hit the home key), when it’s opened back up, and more.  The  AppDelegate  object is stored as a property on the  UIApplication  class and is accessible from anywhere in your objective-C classes.  The header and implementation file for your  AppDelegate  is generated when you create your project and you don’t have to make any modifications for it to work.  However, that doesn’t mean we can’t make changes and make use of the  AppDelegate .  We’re going to keep this simple and just add a new NSString  property to the delegate. AppDelegate is handling special UIApplication states. This lets you do initialization/cleanup of your app at the right time.So basically the ...
Read more

Designated Initializers in Objective - C

Object construction in Objective C is a two phase procedure:---> 1.  First the object has to be allocated in memory, hence the ‘alloc’ message we always see when a object is invoked this way (and not for example via a ‘get…’, which would be a Factory): 2. Second phase involves object initialization which is quite similar to what would be a constructor in C++. When we implement method ‘init’ (which is just a convention) we have to take care on superclass designated initializer .   MyObject* obj1 = [[MyObject alloc] init]; Designated initializer :-->   Designated initializer is the method that best set up our object between all initializer methods. - ( id ) init: - ( id ) initWithColor:( NSColor *)color; - ( id ) initWithColor:( NSColor *)color andSize:( NSInteger )size; What method do you think is the most complete? Our third method includes two parameter while the other only one or none. Now, we got a pattern that you are going to...
Read more