Tick.swift

Tick.swift

import Combine
import SwiftUI

class _Tick: ObservableObject {
  @Published var now: Date = .now

  let timer: Publishers.Autoconnect<Timer.TimerPublisher>
  init(every: TimeInterval = 1) {
    timer = Timer.publish(every: every, on: .main, in: .common)
      .autoconnect()
    timer.assign(to: &$now)
  }

  deinit {
    timer.upstream.connect().cancel()
  }

  var today: Date {
    Calendar.autoupdatingCurrent.date(from: Calendar.autoupdatingCurrent.dateComponents([.year, .month, .day], from: now))!
  }
}

@propertyWrapper
struct Tick: DynamicProperty {
  @StateObject private var tick: _Tick
  init(every: TimeInterval = 1) {
    _tick = StateObject(wrappedValue: .init(every: every))
  }

  var wrappedValue: _Tick {
    tick
  }
}

Usage

struct ContentView: View {
  @Tick var tick
}