The Ultimate iOS Interview Playbook: Conquer Swift, frameworks, design patterns, and app architecture [Team-IRA]

✍ Scribed by Avi Tsadok

• Publisher: Packt Publishing
• Year: 2023
• Tongue: English
• Leaves: 320
• Category: Library

✦ Synopsis

Take your interview skills to the next level by reviewing hundreds of real-world interview questions and coding examples Purchase of the print or Kindle book includes a free PDF eBook

Key Features

• Solve complex design and architecture tasks
• Develop mature and complete answers to commonly asked questions
• Enhance your interview prospects by building a strong developer brand through publications and online projects

Book Description

As an iOS developer, you must possess a diverse skill set encompassing Swift coding, design knowledge, and mastery of development tools. And while the demand for iOS developers remains high, the competition for landing your dream job has intensified in recent years. Being a skilled iOS developer is no longer enough — acing interviews is now just as essential as having technical expertise.

In The Ultimate iOS Interview Playbook, you'll discover innovative ways to stand out as an iOS developer and pass every job interview. It will guide you to build your developer brand and present your skills to potential employers. This comprehensive guide covers over 100 interview questions, from Swift fundamentals and frameworks to complex design patterns and app architecture. You'll learn how to approach coding assessments like a pro and avoid red flags that could hinder your chances of success.

Drawing from the author’s experience of interviewing hundreds of iOS developers and having been a candidate themself, this book addresses the challenges of showcasing your skills and knowledge within a limited timeframe.

By the end of this book, you'll be ready to excel in any iOS interview, demonstrating your strengths and confidently tackling even the most challenging questions, ultimately paving the way to secure the job you've always wanted.

What you will learn

• Gain insights into how an interview process works
• Establish and capitalize on your iOS developer brand
• Easily solve general Swift language questions
• Solve questions on data structures and code management
• Prepare for questions involving primary frameworks such as UIKit, SwiftUI, and Combine Core Data
• Identify the "red flags" in an interview and learn strategies to steer clear of them

Who this book is for

Designed for iOS developers of all levels, from juniors to seniors, this book is a valuable resource for anyone who wants to enhance their interview skills in iOS development. Basic knowledge of iOS development and Swift is necessary to get started with this book.

Table of Contents

1. Before the Interview
2. Going through The Interview Process
3. Developer Branding
4. Data Structures and Algorithms
5. The Swift Programming Language
6. Managing Your Code
7. Building Great User Experiences with UIKit
8. SwiftUI and Declarative Programming
9. Understanding Persistent Memory
10. Libraries Management
11. Design Patterns to Solve Complex Questions
12. Drilling into App Architecture
13. Acing the Coding Assessment

✦ Table of Contents

Cover
Front cover
Copyright and credit page
Contributors
Table of Contents
Preface
Part 1: Everything about Interviews
Chapter 1: Before the Interview
Performing company research
Knowing where you’re going is part of the interview
Company profiles affect our answers
Learning the company characteristics
Building the unofficial company profile
Building our resume
A resume is like a book or a movie
Structuring the resume outline
Working on design and layout
What is the personal information part?
Formulating the personal summary section
Listing our expertise
Skills
Miscellaneous
Avoiding red flags
Inviting another set of eyes
Preparing for the interview
Taking our time
Technical, personal, and logistics preparations
Summary
Chapter 2: Going through the Interview Process
Understanding the hiring process
Learning the hiring funnel
Distinguishing between different companies
Getting ready for the screening interview
What does the screening interview include?
Send a thank-you email
All about the iOS technical interview
Worked-on projects
Answering Swift and algorithm questions
Solving basic questions about UIKit and SwiftUI
Mastering development tools
Cracking the coding interview
Live coding interview
Working on a home assessment
Passing the architecture interview
Summary
Chapter 3: Developer Branding
Understanding the importance of developing a brand
Learning what a brand is
Increasing our chances of passing the resume scanning
Increasing our chances of getting an offer
Expanding our network
How to start building your brand
Contributing to the community
Being a star in Stack Overflow
Maintaining a public GitHub repository
Joining an open source project
Writing content
Being experts
Improving wording and expression capabilities
Increasing our network
Making the world aware of our knowledge
Combining all and more
Understanding that every in-person interaction is important
Summary
Part 2: Swift Language and Coding
Chapter 4: Data Structures and Algorithms
Learning the importance of data structures
Increasing efficiency
Making our code modular
Reusing our code
Using data structures for an API
Answering classes and struct questions
“What’s the difference between a class and a struct?”
“Which is better, a class or a struct?”
“Why are structs faster than classes?”
Answering questions about Swift array
“Please list the Swift array advantages”
“How to remove duplicates from an array?”
“How do you implement a queue using an array?”
“How do you create a new array by mapping the elements of an existing array in Swift?”
Covering the Codable protocol
“How do you handle optional properties when using the Codable protocol?”
“How do you use CodingKeys enumeration to map the keys in a JSON object to the properties of a custom data type?”
“How can you convert a formatted date string to a date object in Codable?”
Preparing for dictionary- and set-related interview questions
“Can you use a dictionary to store configuration data?”
“How do you use the filter method to select a subset of key-value pairs from a dictionary based on a condition?”
“What is the time complexity of common set operations, such as inserting an element or checking for membership?”
“Is it possible to store any type of data in a set collection in Swift?”
Summary
Chapter 5: The Swift Programming Language
How do we master all Swift features?
Basic Swift features
Answering optionals questions
Solving access-level questions
Handling questions about Closures
Advanced Swift language features
Solving computed and lazy variables questions
Solving extensions questions
Solving generics questions
Solving error-handling questions
Solving protocol questions
Solving memory management questions
Summary
Chapter 6: Managing Your Code
Planning
“How do you create a project timeline and plan for the iOS app’s development process?”
“How do you estimate development time for a task?”
“How do you create a technical design document for an iOS task?”
Testing
“What is the meaning of unit and integration testing in the context of iOS development?”
“How do you perform performance testing in iOS applications?”
“Can you explain what it means to write a testable code?”
Debugging
“Can you explain how to debug memory leaks in iOS applications?”
“Can you explain how to debug UI-related issues in iOS applications?”
“How do you debug performance issues in iOS applications?”
Documentation
“Can you explain how you document your iOS code?”
“Can you explain how to document design patterns and best practices in iOS development?”
“How do you handle the documentation of code that multiple team members are developing?”
Summary
Part 3: The Frameworks
Chapter 7: Building Great User Experiences with UIKit
Answering questions about Auto Layout
“Can you explain what content hugging and compression resistance are in Auto Layout and how they are used to control the layout of UI elements?”
“Can you explain how to use size classes in Interface Builder to adapt layouts for different screen sizes and orientations?”
“What is the purpose of the safe area in Auto Layout, and how do you ensure that your views are properly positioned within the safe area?”
Solving UIView questions
“Can you explain how the responder chain works in iOS?”
“How can you respond to device orientation changes in UIView?”
“Why does UIView not have a ‘viewDidAppear’ method as UIViewController does?”
“Can you explain the difference between setNeedsLayout, layoutSubviews, and layoutIfNeeded in UIView? When would you use each of these methods, and how do they impact the layout process?”
“What is the difference between the frame and bounds properties?”
Understanding everything about UIViewController
“Can you list all the life cycle events or methods of a UIViewController, in the order in which they occur?”
“Can you explain the concept of UIViewController containment? How would you implement it in your app?”
“How do you pass data between view controllers in iOS?”
Making sure we are ready with UITableView
“How does the queuing mechanism work in a UITableView, and what are some best practices for optimizing its performance?”
“What is pagination in UITableView, and how would you implement it to efficiently load and display large amounts of data while maintaining good performance and user experience?”
“What are the different approaches for adjusting cell size in a UITableView, and how do you determine the optimal size for cells based on the content they will display?”
Performing navigation well
“What is the purpose of the navigationItem property in a view controller, and how can you use it to customize the behavior and appearance of a navigation bar in iOS development?”
“What are some of the preset options for presenting a UIViewController in iOS, and why is it important to understand these options?”
“How would you design a navigation system for an iOS app using the coordinator pattern, where view controllers don’t decide where to go next, and a coordinator object is responsible for managing the navigation flow?”
Empowering user experience with animations
Going over the core concepts of animation in UIKit
“How can you create custom transitions between UIViewControllers in an iOS app?”
Summary
Chapter 8: SwiftUI and Declarative Programming
Entering a new era of development
Understanding declarative programming
“What’s the difference between declarative programming and the “classic” programming paradigm, also known as imperative programming?”
“How does declarative programming help handle state management in iOS apps?”
Learning states and observable objects
“Can you explain the differences and use cases for the @State and @Binding property wrappers in SwiftUI?”
“What is the purpose of @ObservedObject in SwiftUI, and in what situations would you use it instead of @State or @Binding?”
Navigating SwiftUI views
“How do you pass data between views using the SwiftUI navigation system?”
“Can you explain how to use @Environment(.presentationMode) to dismiss a presented view in SwiftUI navigation?”
Expertise with the SwiftUI life cycle
“How does SwiftUI handle state changes during the view life cycle?”
“How do you use the onChange modifier in SwiftUI, and what state changes does it respond to?”
Expertise in Combine
“Can you provide an example of how you would use Combine in an iOS app?”
“How do you debug a Combine stream?”
Summary
Chapter 9: Understanding Persistent Memory
Mastering Core Data questions
“How do you design a Core Data Stack that supports concurrency while ensuring thread safety, and how can you use NSManagedObjectIDs in a multi-threaded environment to facilitate this?”
“What would your Core Data data model look like for a recipe app that includes ingredients, cooking instructions, and user ratings?”
“How would you approach testing Core Data in an iOS app?”
Handling persistent state with UserDefaults
“Explain how an iOS app and its extensions can share data using UserDefaults. What steps are involved in setting up and using UserDefaults to share data between an app and its extensions?”
“Can you explain how to store a struct or a class in UserDefaults in an iOS app?”
Storing sensitive information in the Keychain
“What is a Keychain Access Group, and how can it be used to securely share Keychain items between different components of an iOS app, such as the app and its extensions?”
Working with the filesystem
“Can you explain the purpose of each of the following folders in an iOS app: Documents, Library, Cache, and Temp? How would you decide which folder to use for storing different types of files in your app?”
Summary
Chapter 10: Libraries Management
Mastering CocoaPods
Learning how CocoaPods is built
“What best practices do you follow when working with CocoaPods, and why are they important?”
“What is the difference between pod update and pod install?”
Learning about the Swift Package Manager
Creating a Swift package
Going over the package manifest and folders
Swift package common commands
Using a Swift package
“What are the advantages and disadvantages of using the SPM compared to CocoaPods?”
“What are some best practices for organizing and structuring Swift packages to optimize build times and minimize dependency conflicts?”
Summary
Part 4: Design and Architecture
Chapter 11: Design Patterns to Solve Complex Questions
Building a UI with MVC/MVVM
Solving different problems with MVC and MVVM
Learning MVC
Exploring MVVM
“How would you implement navigation in an MVVM architecture, considering that the ViewModel should not have knowledge of the View?”
“Why is the MVVM architecture considered good for testability in iOS app development?”
Decoupling with Dependency Injection
Using constructor injection
Simplifying things with setter injection
Using pure functions with method injection
Decoupling our code using protocols
Communicating using delegation
“How does the delegation pattern differ from other communication patterns, such as notifications or closures, in Swift?”
Sharing a state using Singleton
“How would you avoid using a Singleton in your code? Can you describe some of the alternative approaches you might consider?”
“Can you describe the potential issues with using Singletons in a multithreaded environment, and how can these be addressed?”
Improving performance with Concurrency
Working with GCD
Creating advanced queues with OperationQueue
Blocking threads with NSLock
Using the Combine Future publisher to implement async operations
Going over concurrency development best practices
Summary
Chapter 12: Drilling into App Architecture
All about the Separation of Concerns principle
Defining the Separation of Concerns principle
Explaining the importance of SoC
Going practical with the Separation of Concerns principle
Designing app architecture
Breaking the architecture into application layers
Learning about data flow
Designing an offline-first system architecture
The architecture design interview
Entering the head of our interviewer
Approaching the mission
Starting the design
Communicating with the interviewer
Summary
Chapter 13: Acing the Coding Assessment
Succeeding in live coding
Learning about the different live coding tests
Preparing ourselves for the coding interview
Starting to code
Coding like a pro
Excelling in a home assessment
What does a home assessment look like?
The different skills being tested in a home assessment
Going over examples
Avoiding red flags
Inability to explain or defend a solution
Dichotomic thinking
Limited error handling
Poor code quality
Summary
Index
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