YearMonthDay.swift

import Foundation

struct YearMonthDay {
    var year: Int
    var month: Int
    var day: Int
    
    /// Extracts yearMonthDay from Date, using calendar.
    static func from(_ date: Date, calendar: Calendar = Calendar(identifier: .gregorian)) -> YearMonthDay {
        let components = calendar.dateComponents([.year, .month, .day], from: date)
        return YearMonthDay(year: components.year!, month: components.month!, day: components.day!)
    }
    
    func date(calendar: Calendar = Calendar(identifier: .gregorian)) -> Date {
        var components = DateComponents()
        components.year = year
        components.month = month
        components.day = day
        return calendar.date(from: components)!
    }
}

extension YearMonthDay: Equatable {}