What is Combine? Combine Framework provides an API for processing async events over time such as user-input, network response, and other dynamic data. What is the purpose of Combine? The purpose of Combine is to simplify the management of async events and data streams. Publishers Publisher declares that a type can transit a sequence of values over time. A publisher delivers elements to one or more Subscriber instances. class PostService { func fetchPosts() -> AnyPublisher<[Post], Error> { guard let url = URL(string: "https://jsonplaceholder.typicode.com/posts") else { fatalError("Invalid URL") } return URLSession.shared.dataTaskPublisher(for: url) .map(\.data) .decode(type: [Post].self, decoder: JSONDecoder()) .receive(on: DispatchQueue.main) .eraseToAnyPublisher() } } Subscribers Subscriber is a protocol that declares a type that can receive input from a publisher. A Subscriber instance receives a stream of elements from a Publisher. ...

When was it introduced? It was introduced in Swift 5.5 at WWDC 2021. You can find the more comprehensive info about Modern Concurrency in Swift Concurrency Manifesto. What are actors? Actors eliminate shared mutable state and explicit synchronization through deep copying of all the data that passed to an actor to a message sent and preventing direct access to actor state. Actors are reference types. actor DatabaseManager { private var data: [String: String] = [:] func readData(key: String) -> String? { data[key] } func writeData(key: String, value: String) { data[key] = value } } What is an asynchronous function? The asynchronous function or asynchronous method can be suspended while it is partway through execution. It can pause in the middle when it’s waiting for something. ...

What is the Thread? A Thread is a small set of instructions that can be executed independently from the main program. Threads are often used to improve program performance by allowing multiple tasks to be executed at the same time. The Thread has its own stack, registers, and program counters. Threads share memory address space, and it is possible to communicate between Threads using shared memory space. ...

What is DispatchGroup? DispatchGroup provides a mechanism to track the completion group of tasks. How DispatchGroup works? DispatchGroup has three main methods, enter, leave and notify, that allow you to control the completion of a specific task. let dispatchGroup = DispatchGroup() dispatchGroup.enter() dispatchGroup.leave() dispatchGroup.notify(queue: .main) {} Let`s talk about each of these methods. enter — manually indicate a block has entered group. leave — manually indicate a block in the group has been completed. notify(queue: ) — schedule a block to be submitted to a queue when all the blocks associated with a group have been completed. The queue parameter is the queue to which the supplied block will be submitted when the group is complete. ...

What is concurrency? The system can perform multiple tasks simultaneously. By tasks, I mean code or instructions. Modern computer chips have multiple cores that allow developers to create and run various tasks on multiple cores. Even if your chip has one core operating system it will provide context switching mechanism by enabling it to execute multiple tasks concurrently. Material about processes, threads I will skip explaining concepts about processes and threads because it is a vast topic, and it will take a lot of time to explain it. I attached links to the material to help you understand it more deeply. https://youtu.be/4rLW7zg21gI?si=49hq8Wrbpmeev41k https://youtu.be/r2__Rw8vu1M?si=b7b257Qu4Bty7OxA I will focus on implementation. ...