Combine Framework (Subject, CombineLatest, Zip)

Subject Publisher

It’s a special kind of publisher that allows you to emit values manually. It acts as both a publisher and a subscriber. This is useful when you want to bridge imperative code (like button taps) cal

Use Cases of Subject:

• To convert imperative code (like delegates, closures, or events) into reactive streams.
• Manually send values that might come from user input or external triggers.

There are two main types of subjects:

1. PassthroughSubject:

• It doesn’t store the values, meaning subscribers won’t get any previously emitted values when they subscribe. If a subscriber subscribes after values have already been emitted, they will not receive the past values.

Example with PassthroughSubject

Here’s an example to understand the workings of PassthroughSubject:

// Create a PassthroughSubject that will publish integers and never fail.
let subject = PassthroughSubject<Int, Never>()
// Subscriber #1
let subscription1 = subject.sink { value in
    print("Subscriber #1 received value: \(value)")
}
// Send values through the subject
subject.send(10)
subject.send(20)
// Subscriber #2 subscribes after some values have already been sent
let subscription2 = subject.sink { value in
    print("Subscriber #2 received value: \(value)")
}
// Send another value
subject.send(30)