let now = Date()
let calendar = Calendar.current
let yesterday = calendar.date(
    byAdding: Calendar.Component.day,
    value: -1, to: now)!
let tomorrow = calendar.date(
    byAdding: .day, value: 1, to: now)!

let nextMonth = calendar.date(
    byAdding: .month, value: 1, to: now)!

let nextYear = calendar.date(
    byAdding: .year, value: 1, to: now)!

print("now = \(now)")
print("yesterday = \(yesterday)")
print("tomorrow = \(tomorrow)")
print("nextMonth = \(nextMonth)")
print("nextYear = \(nextYear)")