Generalized Sidebar

SideBarView.swift

import SwiftUI

enum MenuItem: String, CaseIterable, Identifiable {
    case pinned = "Pinned"
    case activity = "Activity"
    case legal = "Legal"

    var id: MenuItem { MenuItem(rawValue: self.rawValue) ?? .pinned }
}

class MenuItemViewModel: ObservableObject {
    @Published var isMenuOpened:Bool
    @Published var selectedMenuItem: MenuItem
    
    init(isMenuOpened: Bool = false, selectedMenuItem: MenuItem = .pinned) {
        self.isMenuOpened = isMenuOpened
        self.selectedMenuItem = selectedMenuItem
    }
}

struct SideBar<Content,Item>: View where Content: View, Item: Identifiable {
    typealias Completion = () -> Void
    private var items: [Item]
    private let content: (Item.ID, @escaping Completion) -> Content
    @EnvironmentObject var menuItemViewModel: MenuItemViewModel
    let sidebarWidth = UIScreen.main.bounds.size.width / 1.2
    
    init(items: [Item], content: @escaping (Item.ID, @escaping Completion) -> Content) {
        self.content = content
        self.items = items
    }
    
    var body: some View {
        HStack {
            VStack {
                ForEach(items) { item in
                    self.content(item.id) {
                        self.menuItemViewModel.isMenuOpened.toggle()
                        self.menuItemViewModel.selectedMenuItem = item.id as? MenuItem ?? MenuItem.pinned
                    }
                }
                Spacer()
            }
            .foregroundColor(.primary)
            .frame(width: sidebarWidth)
            .background(Color.white.edgesIgnoringSafeArea(.all))
            .overlay(
                Rectangle()
                .stroke(Color.primary.opacity(0.2), lineWidth: 1)
                .shadow(radius: 2)
                .edgesIgnoringSafeArea(.all)
            )
            .offset(x: menuItemViewModel.isMenuOpened ? 0 : -sidebarWidth)
            
            
            Spacer()
        }
        .background(Color.primary.opacity(menuItemViewModel.isMenuOpened ? 0.2 : 0).edgesIgnoringSafeArea(.all))
    }
}

struct SideBarView: View {
    @StateObject var viewModel = MenuItemViewModel()
    let sidebarWidth = UIScreen.main.bounds.size.width / 1.2 // 1
    
    private var menuContent: some View {
        switch viewModel.selectedMenuItem {
        case .pinned:
            return Text("Pinned")
        case .activity:
            return Text("Activity")
        case .legal:
            return Text("Legal")
        }
    }
    
    var body: some View {
        ZStack {
            GeometryReader { _ in
                VStack {
                    Button {
                        withAnimation {
                            viewModel.isMenuOpened.toggle()
                        }
                    } label: {
                        Image(systemName: "line.horizontal.3")
                            .resizable()
                            .frame(width: 24, height: 24)
                    }
                    .padding()
                    .foregroundColor(Color.primary)
                }
            }
            
            menuContent
            
            SideBar(items: MenuItem.allCases) { item, completion in
                HStack {
                    Button {
                        completion()
                    } label: {
                        Text(item.rawValue)
                    }
                    Spacer()
                }
                .padding(.horizontal)
            }
            .environmentObject(viewModel)
        }
    }
}