SwiftUI Alert example using enum

swift_alert_in_enum.swift

import SwiftUI

enum Message {
    /// A message and OK button
    case information(body: String)
    /// A message and OK button
    case warning(body: String)
    /// A question with YES and NO buttons
    case confirmation(body: String, action: () -> Void)
    /// A question about destractive action with `action` and CANCEL buttons
    case destruction(body: String, label: String, action: () -> Void)
}

extension Message: Identifiable {
    var id: String { String(reflecting: self) }
}

extension Message {
    /// Builder of an Alert
    func show() -> Alert {
        switch self {

        case let .confirmation(body, action):
            return Alert(
                title: Text("Confirmation"),
                message: Text(body),
                primaryButton: .default(Text("YES"), action: action),
                secondaryButton: .cancel(Text("NO")))

        case let .information(body):
            return Alert(
                title: Text("Information"),
                message: Text(body))

        case let .warning(body):
            return Alert(
                title: Text("Warning"),
                message: Text(body))

        case let .destruction(body, label, action):
            return Alert(
                title: Text("Confirmation"),
                message: Text(body),
                primaryButton: .destructive(Text(label), action: action),
                secondaryButton: .cancel())
        }
    }
}

extension View {
    func alert(with message: Binding<Message?>) -> some View {
        self.alert(item: message) { $0.show() }
    }
}

struct ContentView: View {

    var variants: [Message] = [

        .confirmation(body: "Sure?", action: {
            print("Confirmed")
        }),

        .destruction(body: "Are you want to delete files?", label: "DELETE", action: {
            print("Deleted")
        }),

        .warning(body: "You reached the limit!"),

        .information(body: "Rest is what your body needs.")

    ]

    @State var message: Message? = nil

    var body: some View {
        Button(action: {
            self.message = self.variants.randomElement()!
        }) {
            Text("Let's alert")
        }

        .alert(with: $message)
    }
}