Making a combine passthrough publisher less global - ios

Question

Swift 5, iOS 13
I want to use passthroughSubject publisher; but I my gut tells me its a global variable and as such very poor practice. How can make this global variable less global, while still being usable. Here's some code to show what I talking about.
I know there are a dozen other ways to do this, but I wanted to create some simple code to illustrate the issue.
import SwiftUI
import Combine
let switcher = PassthroughSubject<Void,Never>()
struct SwiftUIViewF: View {
#State var nextPage = false
var body: some View {
VStack {
Text("Switcher")
.onReceive(switcher) { (_) in
self.nextPage.toggle()
}
if nextPage {
Page1ViewF()
} else {
Page2ViewF()
}
}
}
}
struct Page1ViewF: View {
var body: some View {
Text("Page 1")
.onTapGesture {
switcher.send()
}
}
}
struct Page2ViewF: View {
var body: some View {
Text("Page 2")
.onTapGesture {
switcher.send()
}
}
}
struct SwiftUIViewF_Previews: PreviewProvider {
static var previews: some View {
SwiftUIViewF()
}
}

Answer 1

Here is possible solution - to hold it in parent and inject into child views:
struct SwiftUIViewF: View {
let switcher = PassthroughSubject<Void,Never>()
#State var nextPage = false
var body: some View {
VStack {
Text("Switcher")
.onReceive(switcher) { (_) in
self.nextPage.toggle()
}
if nextPage {
Page1ViewF(switcher: switcher)
} else {
Page2ViewF(switcher: switcher)
}
}
}
}
struct Page1ViewF: View {
let switcher: PassthroughSubject<Void,Never>
var body: some View {
Text("Page 1")
.onTapGesture {
self.switcher.send()
}
}
}
struct Page2ViewF: View {
let switcher: PassthroughSubject<Void,Never>
var body: some View {
Text("Page 2")
.onTapGesture {
self.switcher.send()
}
}
}

Answer 2

An example using #EnvironmentObject.
Let SDK take care of observing / passing things for you, rather than setting up yourself.
Especially when your usage is a simple toggle.
import SwiftUI
import Combine
final class EnvState: ObservableObject { #Published var nextPage = false }
struct SwiftUIViewF: View {
#EnvironmentObject var env: EnvState
var body: some View {
VStack {
Text("Switcher")
if env.nextPage {
Page1ViewF()
} else {
Page2ViewF()
}
}
}
}
struct Page1ViewF: View {
#EnvironmentObject var env: EnvState
var body: some View {
Text("Page 1")
.onTapGesture {
env.nextPage.toggle()
}
}
}
struct Page2ViewF: View {
#EnvironmentObject var env: EnvState
var body: some View {
Text("Page 2")
.onTapGesture {
env.nextPage.toggle()
}
}
}
struct SwiftUIViewF_Previews: PreviewProvider {
static var previews: some View {
SwiftUIViewF().environmentObject(EnvState())
}
}