I wrote my UserView for day 60's challenge like this:

import SwiftUI

struct UserView: View {
    var users: [User]
    var user: User

    var body: some View {
        VStack {
            Form {
                Section {
                    HStack {
                        Text("Age: ")
                            .fontWeight(.bold)
                        Spacer()
                        Text("\(user.age)")
                    }
                    HStack {
                        Text("Company: ")
                            .fontWeight(.bold)
                        Spacer()
                        Text(user.company)
                    }
                    HStack {
                        Text("Email: ")
                            .fontWeight(.bold)
                        Spacer()
                        Text(user.email)
                    }
                    HStack {
                        Text("Address: ")
                            .fontWeight(.bold)
                        Spacer()
                        Text(user.address)
                            .multilineTextAlignment(.trailing)
                    }

                    HStack {
                        Text("Date registered: ")
                            .fontWeight(.bold)
                        Spacer()
                        Text("\(user.registered, formatter: itemFormatter)")
                    }
                }

                Section(header: Text("About")) {
                    Text(user.about)
                        .padding(.vertical)
                }

                Section(header: Text("Friends")) {
                    ForEach(user.friends, id: \.id) { friend in
                        NavigationLink(destination: findFriend(from: friend, in: users)) {
                            Text(friend.name)
                        }
                    }
                }
            }
        }
        .navigationBarTitle(Text(user.name))
    }

    func findFriend(from friend: Friend, in users: [User]) -> some View {
        guard let user = users.first(where: { $0.id == friend.id }) else {
            return AnyView(Text("No match"))
        }
        return AnyView(UserView(users: users, user: user))
    }
}

private let itemFormatter: DateFormatter = {
    let formatter = DateFormatter()
    formatter.dateStyle = .short
    return formatter
}()

//struct UserView_Previews: PreviewProvider {
//    static var previews: some View {
//        UserView()
//    }
//}

I have two questions about things I think I've done slightly badly.

1. How do I get the preview to work? I tried doing UserView(users: [User()], user: User()) but I got the error "Missing argument for parameter 'from' in call" and I couldn't work out how to create a dummy User() for the purposes of the preview.

2. As you can see, I use the findFriend function to return a UserView which contains the user corresponding to the friend, but I wanted to make sure that if (for some reason) the underlying JSON specified a friend which didn't exist, I could return some view which indicated that in some way. My way works, but I was wondering whether there was a more elegant way to achieve this?

Just in case it's relevant, my User and Friend structs are defined thus in ContentView:

struct User: Codable {
    var id: String
    var isActive: Bool
    var name: String
    var age: Int
    var company: String
    var email: String
    var address: String
    var about: String
    var registered: Date
    var tags: [String]
    var friends: [Friend]
}

struct Friend: Codable {
    var id: String
    var name: String
}