Encapsulates PassthroughSubject / CurrentValueSubject

CurrentValueBacked.swift

/// Property Wrapper that wraps an `AnyPublisher`, which is backed by a `CurrentValueSubject`. This is to make it possible  to easily expose just a publisher to consumers of a type,
/// without also exposing the `CurrentValueSubject` to consumers, effectively allowing for public reads and private writes of a publisher.
@propertyWrapper
struct CurrentValueBacked<Output> {

  private var subject: CurrentValueSubject<Output, Never>
    init(_ output: Output) {
        subject = CurrentValueSubject<Output, Never>(output)
  }

  var wrappedValue: AnyPublisher<Output, Never> {
    subject.eraseToAnyPublisher()
  }

  var projectedValue: CurrentValueBacked<Output> {
    self
  }

  func send(_ value: Output) {
    subject.send(value)
  }
}

extension CurrentValueBacked where Output == Void {
    
    func send(_ output: Output) {
        subject.send(output)
    }
    
    var value: Output {
        get {
            return subject.value
        }
       
        set {
            subject.value = newValue
        }
    }
}

PassthroughBacked.swift

import Foundation
import Combine

@propertyWrapper
struct PassthroughBacked<Output> {

  private var subject: PassthroughSubject<Output, Never>
  init() {
    subject = PassthroughSubject<Output, Never>()
  }

  var wrappedValue: AnyPublisher<Output, Never> {
    subject.eraseToAnyPublisher()
  }

  var projectedValue: PassthroughBacked<Output> {
    self
  }

  func send(_ value: Output) {
    subject.send(value)
  }
}

extension PassthroughBacked where Output == Void {
  func send() {
    subject.send()
  }
}