ObservablePublisher.swift

import Combine
import Foundation
import SwiftUI

class ObservablePublisher<Output>: ObservableObject {
	@Published var output: Output?
	@Published var error: Swift.Error?
	private var observer: AnyCancellable?
	
	init() {}
	
	init<P: Publisher>(_ publisher: P) where P.Output == Output {
		self.load(publisher)
	}
	
	var isLoading: Bool {
		self.output == nil && self.error == nil
	}
	
	func load<P: Publisher>(_ publisher: P) where P.Output == Output {
		self.output = nil
		self.error = nil
		
		self.observer?.cancel()
		self.observer = publisher
			.receive(on: RunLoop.main)
			.sink { completion in
				switch completion {
				case let .failure(error):
					self.error = error
				case .finished:
					break
				}
			} receiveValue: { output in
				self.output = output
			}
	}
}