TimestampViewModel.swift

import SwiftUI

class ViewModel: ObservableObject {
  @Published var timestamp: TimeInterval
  @Published var date: Date
  
  var timestampFormatter: NumberFormatter = {
    var formatter = NumberFormatter()
    formatter.allowsFloats = false
    return formatter
  }()
  
  var timeZoneOffsetString: String {
    let hourDifference: Int = TimeZone.current
      .secondsFromGMT(for: date) / 3600
    if hourDifference == 0 {
      return "UTC"
    } else if hourDifference > 0 {
      return "UTC +\(hourDifference)"
    } else {
      return "UTC \(hourDifference)"
    }
  }
  
  init() {
    let date = Date()
    self.timestamp = date.timeIntervalSince1970
    self.date = date
  }
}