Combine - Reactive Programming in iOS (2025)

Hello, I am aguma, a current iOS developer.

I started studying development at the age of 31 while working in another field, and I am currently working hard on iOS development at an affiliate of Nekara.

• Started studying development at a boot camp in early 2020 (at the age of 31)

• New iOS developer job at one of Nekara's affiliates at the end of 2021 (age 33)

• Still working at the same company as of 2025

As a non-major who started developing late in his 30s, I sympathize more deeply than anyone else with the frustration and difficulties of those preparing for employment. I also know well the efforts of those who are preparing for a job change by investing their precious time in order to achieve steady growth.

As I have been running towards my dream of becoming a developer for two years with no income at all, I would like to provide quality lectures at a reasonable price to those who are following a similar path.

Although the entire curriculum is not yet complete, when all the lectures I have planned are released, I will responsibly create a system where you can acquire all the knowledge necessary for a 1-2 year iOS developer by just following my lectures .

Korea's first iOS Combine lecture

I have taken more Combine lectures than anyone else.

Udemy , Kodeco (formerly Raywenderich), Youtube , Apple official documentation , etc...

I have collected and organized almost all the lectures that can be found online into this one lecture. I think I paid about 200,000 to 300,000 won just by watching many free and paid lectures. However, I felt that there was no good Combine lecture for the price, so I made it myself.

We've tried to create a very detailed lecture that can be helpful to both developers who don't know Combine and students who can simply use Combine.

Combine - Reactive Programming on iOS

The main goal of this lecture is to help you write your own Combine code after completing the lecture .

When I first started studying Combine, I thought I understood it after reading various lectures and articles.

When it came to actually writing code, I had no idea where to start. 🤯

So when I was creating this course, I put the goal of “You should be able to implement Combine code yourself with just this course!” first and foremost in mind.

💡 Practice, not theory!

It is designed so that you can learn it by writing code with your own hands , rather than just reading and understanding it.

🔥 Master Combine completely in this one lecture!

After taking this course, you will be able to freely utilize Combine in your iOS development. 🚀

🌟 Essential skills for iOS developers! 🌟

📌 Reactive Programming & Combine ,

Key technologies that are never left out of iOS announcements!

🚀 Master the Combine Framework, which is gaining attention in the iOS recruitment market .

Take your development competitiveness to the next level! 💡 🔥

🎨 Self-made Reactive Programming - Marvel Diagram 🎨

📌 All operators covered in the lecture at a glance!

Don't worry about Operators in Reactive Programming that are difficult to understand!

🔍 Through intuitive marble diagrams ,

We created it ourselves so that even complex concepts can be easily understood.

⚡️ Quickly learn the core principles of Combine with visual learning! 🚀

🚀 Get a feel for real-world code with Combine examples!

✅ Complex asynchronous scenarios can also be easily implemented using Combine!

Develop practical skills through various examples so that you can apply them in real projects.

📱 Full support for UIKit & SwiftUI!

• Learn how to implement the same functionality in both UIKit and SwiftUI versions !

• It is organized as a separate lecture so that you can learn without burden even if you don't know UIKit or SwiftUI!

💡 Build solid practical experience to be able to handle Combine skillfully in any environment! 🚀

The same Combine code was created in two versions: UIKit and SwiftUI .

It is structured so that you can take the course by selecting only one of UIKit or SwiftUI.

We created this as a separate lecture so that even those who are familiar with only one side can learn without any burden.

💡 Completely summarize the core concepts of Combine in this one lecture! 🚀

🛠 From Publisher → Subscriber → Operator , learn all the keywords you need in practice without missing anything! ✅

📌 Summary of keywords explained in the lecture ⬇ ⬇ ⬇

Publisher

• Foundation built-in Publisher (URLSession, Timer, NotificationCenter)

• @Published

• Convenience Publisher(Just, Fail, Empty, Future, ... )

• Subject(PassthroughSubject, CurrentValueSubject)

  
  

• eraseToAnyPublisher, AnyPublisher

Subscriber

• sink

• assign

Subscription

• Cancellable, AnyCancellable

• cancel

Operator(1) - Basic Operator

• map

• filter

• reduce

• scan

• compactMap

• replaceNil

Operator(2) - Time Controlling Operator

• Delay

• timeout

• throttle

• debounce

Operator(3) - Combining Operator

• merge

• zip

• combineLatest

• flatmap

• switchToLatest

Operator(4) - Error Handling Operator

• tryMap

• mapError

• setFailureType

• retry

• catch

• replaceError

• assertNoFailure

Debugging Operator

• print

• handleEvents

• breakpoint, breakpointOnError

  
  

Resource Management

• share

• multicast

  
  

Scheduler

• Runloop

  • Runloop mode: default, tracking, common

• DispatchQueue.main vs Runloop.main

  
  

  
  

Things to note before taking the class