How to check if a view is displayed on the screen? (Swift 5 and SwiftUI)

I have a view like below. I want to find out if it is the view which is displayed on the screen. Is there a function to achieve this?

struct TestView: View {
    var body: some View {
        Text("Test View")
    }
}

You could use onAppear on any kind of view that conforms to View protocol.

struct TestView: View {
    @State var isViewDisplayed = false
    var body: some View {
        Text("Test View")
        .onAppear {
            self.isViewDisplayed = true
        }
        .onDisappear {
            self.isViewDisplayed = false
        }
    }

    func someFunction() {
        if isViewDisplayed {
            print("View is displayed.")
        } else {
            print("View is not displayed.")
        }
    }
}

PS: Although this solution covers most cases, it has many edge cases that has not been covered. I'll be updating this answer when Apple releases a better solution for this requirement.