是 swift 中另一个日期的同一周、月、年的日期

Question

了解某个日期是否与另一个日期在同一周（或年份或月份）的最佳方法是什么，最好有扩展名，并且仅使用 Swift？

例如，在 Objective-C 中我有

- (BOOL)isSameWeekAs:(NSDate *)date {
    NSDateComponents *otherDay = [[NSCalendar currentCalendar] components:NSCalendarUnitEra | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay fromDate:self];
    NSDateComponents *today = [[NSCalendar currentCalendar] components:NSCalendarUnitEra | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay fromDate:date];
    return ([today weekOfYear]   == [otherDay weekOfYear] &&
            [today year]         == [otherDay year] &&
            [today era]          == [otherDay era]);
}

请不要提出将Date 连接到NSDate 的解决方案

Answer 1

您可以使用日历方法isDate(equalTo:granularity:)查看如下：

Xcode 11 • Swift 5.1

extension Date {

    func isEqual(to date: Date, toGranularity component: Calendar.Component, in calendar: Calendar = .current) -> Bool {
        calendar.isDate(self, equalTo: date, toGranularity: component)
    }

    func isInSameYear(as date: Date) -> Bool { isEqual(to: date, toGranularity: .year) }
    func isInSameMonth(as date: Date) -> Bool { isEqual(to: date, toGranularity: .month) }
    func isInSameWeek(as date: Date) -> Bool { isEqual(to: date, toGranularity: .weekOfYear) }

    func isInSameDay(as date: Date) -> Bool { Calendar.current.isDate(self, inSameDayAs: date) }

    var isInThisYear:  Bool { isInSameYear(as: Date()) }
    var isInThisMonth: Bool { isInSameMonth(as: Date()) }
    var isInThisWeek:  Bool { isInSameWeek(as: Date()) }

    var isInYesterday: Bool { Calendar.current.isDateInYesterday(self) }
    var isInToday:     Bool { Calendar.current.isDateInToday(self) }
    var isInTomorrow:  Bool { Calendar.current.isDateInTomorrow(self) }

    var isInTheFuture: Bool { self > Date() }
    var isInThePast:   Bool { self < Date() }
}

Answer 2

您可以使用这个基于您提供的 Objective-C 代码的扩展：

extension Date {
    func hasSame(_ components: Calendar.Component..., as date: Date, using calendar: Calendar = .autoupdatingCurrent) -> Bool {
             return components.filter { calendar.component($0, from: date) != calendar.component($0, from: self) }.isEmpty
    }
}

这里的默认日历是autoupdatingCurrent，因此如果用户更改日历，它将相应更新。它还使用可变参数组件，允许您指定任意数量的组件，而无需将它们包装到数组中。

使用示例：

let date1 = Date()
let date2 = Date()
let date3 = Date(timeIntervalSince1970: 30.0)

print(date1.hasSame(.weekOfYear, .day, .hour, as: date2)) // true
print(date1.hasSame(.weekOfYear, as: date3)) // false

编辑

正如@Leo Dabus 所指出的，我们可以在此处使用 set 而不是数组/可变参数 - 这样，如果用户将一些重复项传递给该方法，我们将避免多次比较相同的组件：

extension Date {
    func hasSame(_ components: Set<Calendar.Component>, as date: Date, using calendar: Calendar = .autoupdatingCurrent) -> Bool {
             return components.filter { calendar.component($0, from: date) != calendar.component($0, from: self) }.isEmpty
    }
}