PopUp menu on macOS https://twitter.com/krzyzanowskim/status/1546221730267627523

STPopUpMenu.swift

import AppKit
import SwiftUI

/*
        Text("Menu")
            .popUpMenu {
                NSMenuItem(title: "One", action: nil, keyEquivalent: "")
                NSMenuItem(title: "Two", action: nil, keyEquivalent: "")
            }
*/

struct STPopUpMenu<Label: View>: View {
    @State private var isPresented: Bool = false
    private var content: () -> [NSMenuItem]
    private var label: () -> Label

    init(@STMenuItemsBuilder content: @escaping () -> [NSMenuItem], @ViewBuilder label: @escaping () -> Label) {
        self.content = content
        self.label = label
    }

    var body: some View {
        STPopUpMenuContent(
            isPresented: $isPresented,
            content: content,
            label: {
                label()
                    .contentShape(Rectangle())
                    .onTapGesture {
                        isPresented = true
                    }
            }
        )
    }
}

private struct STPopUpMenuContent<Label: View>: NSViewRepresentable {
    @Binding var isPresented: Bool
    private var content: () -> [NSMenuItem]
    private var label: () -> Label

    init(isPresented: Binding<Bool>, @STMenuItemsBuilder content: @escaping () -> [NSMenuItem], @ViewBuilder label: @escaping () -> Label) {
        self._isPresented = isPresented
        self.content = content
        self.label = label
    }

    func makeNSView(context: Context) -> NSHostingView<Label> {
        NSHostingView(rootView: label())
    }

    func updateNSView(_ nsView: NSViewType, context: Context) {
        context.coordinator.parent = self

        // Update label value
        nsView.rootView = label()

        if isPresented, context.coordinator.currentMenu == nil {
            let menu = NSMenu()
            menu.items = content()
            context.coordinator.currentMenu = menu
            menu.delegate = context.coordinator

            var location: NSPoint? = nil
            if let currentEvent = NSApp.currentEvent {
                location = nsView.convert(currentEvent.locationInWindow, from: nil)
            }

            Task { @MainActor in
                context.coordinator.currentMenu?.popUp(
                    positioning: nil,
                    at: location ?? CGPoint(x: CGRectGetMidX(nsView.frame), y: CGRectGetMidY(nsView.frame)),
                    in: nsView
                )
            }
        } else if !isPresented {
            context.coordinator.currentMenu?.cancelTracking()
            context.coordinator.currentMenu = nil
        }
    }

    func makeCoordinator() -> MyCoordinator<Label> {
        MyCoordinator(parent: self)
    }

    class MyCoordinator<Label: View>: NSObject, NSMenuDelegate {
        var parent: STPopUpMenuContent<Label>
        var currentMenu: NSMenu?

        init(parent: STPopUpMenuContent<Label>) {
            self.parent = parent
        }

        func menuDidClose(_ menu: NSMenu) {
            parent.isPresented = false
        }
    }
}

@resultBuilder
struct STMenuItemsBuilder {
    static func buildBlock() -> [NSMenuItem] { [] }
    static func buildBlock(_ content: NSMenuItem...) -> [NSMenuItem] { content }
    static func buildBlock(_ content: [NSMenuItem]) -> [NSMenuItem] { content }
    static func buildArray(_ components: [[NSMenuItem]]) -> [NSMenuItem] { components.flatMap { $0 } }
}


extension View {
    func popUpMenu(@STMenuItemsBuilder _ content: @escaping () -> [NSMenuItem]) -> some View {
        STPopUpMenu(content: content) {
            self
        }
    }
}