如何在Swift中存儲(chǔ)和格式化天數(shù)/周數(shù)/月數(shù)？

我想創(chuàng)建的不是Date而是簡單的時(shí)間量（即持續(xù)時(shí)間），其單位可以是天、周或月，然后將它們很好地格式化為“1天”、“7天”、”3周“、”1個(gè)月“等。

然而Duration和Measurement<UnitDuration>初始值設(shè)定項(xiàng)都不接受這些單位。

// Type 'Duration' has no member 'days'
let duration: Duration = .days(7)

// Type 'UnitDuration' has no member 'days'
let measurement: Measurement<UnitDuration> = .init(value: 7, unit: .days)

我試圖擴(kuò)展UnitDuration，但它不允許將單位自動(dòng)格式化為復(fù)數(shù)。

extension UnitDuration {
    static let days = UnitDuration(
        symbol: "days",
        converter: UnitConverterLinear(coefficient: 60 * 60 * 24)
    )
}

let measurement: Measurement<UnitDuration> = .init(value: 1, unit: .days)
measurement.formatted(.measurement(width: .wide, usage: .asProvided)) // "1 days" :(

目的是得到這樣的東西：

let onDay: Duration = .days(1)
let eightWeeks: Duration = .weeks(8)
oneDay.formatted() // "1 day"
eightWeeks.formatted() // "8 weeks"