CancelBag.swift

//
//  CancelBag.swift
//  CountriesSwiftUI
//
//  Created by Alexey Naumov on 04.04.2020.
//  Copyright © 2020 Alexey Naumov. All rights reserved.
//

import Combine
import SwiftUI

final class CancelBag {
    var subscriptions = Set<AnyCancellable>()

    func cancel() {
        subscriptions.forEach { $0.cancel() }
        subscriptions.removeAll()
    }

    func collect(@Builder _ cancellables: () -> [AnyCancellable]) {
        subscriptions.formUnion(cancellables())
    }

    @_functionBuilder
    struct Builder {
        static func buildBlock(_ cancellables: AnyCancellable...) -> [AnyCancellable] {
            return cancellables
        }
    }
}

extension AnyCancellable {
    func store(in cancelBag: CancelBag) {
        cancelBag.subscriptions.insert(self)
    }
}

ViewModel.swift

class ViewModel: ObservableObject {
    private var cancelBag = CancelBag()

    @Published var publisher1: Int = 0
    @Published var publisher2: String = "s0"

    init() {
        cancelBag.collect {
            $publisher1.sink { print($0) }
            $publisher2
                .removeDuplicates()
                .sink { print($0) }
        }
    }
}

Read more
https://gist.github.com/nalexn/33f14af1d163ea476ee499c0459824b2
https://nalexn.github.io/cancelbag-for-combine/