Date.FormatStyle Examples and Usage

dates.swift

import SwiftUI
import UIKit

// MARK: - Setup

let twosdayDateComponents = DateComponents(
    year: 2022,
    month: 2,
    day: 22,
    hour: 2,
    minute: 22,
    second: 22,
    nanosecond: 22
)
let twosday = Calendar(identifier: .gregorian).date(from: twosdayDateComponents)!

// MARK: - DateStyle

twosday.formatted(date: .abbreviated, time: .omitted) // "Feb 22, 2022"
twosday.formatted(date: .complete, time: .omitted)    // "Tuesday, February 22, 2022"
twosday.formatted(date: .long, time: .omitted)        // "February 22, 2022"
twosday.formatted(date: .numeric, time: .omitted)     // "2/22/2022"

// MARK: - TimeStyle

twosday.formatted(date: .omitted, time: .complete)  // "2:22:22 AM MST"
twosday.formatted(date: .omitted, time: .shortened) // "2:22 AM"
twosday.formatted(date: .omitted, time: .standard)  // "2:22:22 AM"

// MARK: - DateStyle & TimeStyle

twosday.formatted(date: .abbreviated, time: .complete)  // "Feb 22, 2022, 2:22:22 AM MST"
twosday.formatted(date: .abbreviated, time: .shortened) // "Feb 22, 2022, 2:22 AM"
twosday.formatted(date: .abbreviated, time: .standard)  // "Feb 22, 2022, 2:22:22 AM"
twosday.formatted(date: .complete, time: .complete)     // "Tuesday, February 22, 2022, 2:22:22 AM MST"
twosday.formatted(date: .complete, time: .shortened)    // "Tuesday, February 22, 2022, 2:22 AM"
twosday.formatted(date: .complete, time: .standard)     // "Tuesday, February 22, 2022, 2:22:22 AM"
twosday.formatted(date: .long, time: .complete)         // "February 22, 2022, 2:22:22 AM MST"
twosday.formatted(date: .long, time: .shortened)        // "February 22, 2022, 2:22 AM"
twosday.formatted(date: .long, time: .standard)         // "February 22, 2022, 2:22:22 AM"
twosday.formatted(date: .numeric, time: .complete)      // "2/22/2022, 2:22:22 AM MST"
twosday.formatted(date: .numeric, time: .shortened)     // "2/22/2022, 2:22 AM"
twosday.formatted(date: .numeric, time: .standard)      // "2/22/2022, 2:22:22 AM"

// MARK: - Components

twosday.formatted(.dateTime.day())       // "22"
twosday.formatted(.dateTime.dayOfYear()) // "53"
twosday.formatted(.dateTime.era())       // "AD"
twosday.formatted(.dateTime.hour())      // "2 AM"
twosday.formatted(.dateTime.minute())    // "22"
twosday.formatted(.dateTime.month())     // "Feb"
twosday.formatted(.dateTime.quarter())   // "Q1"
twosday.formatted(.dateTime.second())    // "22"
twosday.formatted(.dateTime.timeZone())  // "MST"
twosday.formatted(.dateTime.week())      // "9"
twosday.formatted(.dateTime.weekday())   // "Tue"
twosday.formatted(.dateTime.year())      // "2022"

// MARK: - Compositing

twosday.formatted(.dateTime.year().month().day().hour().minute().second()) // "Feb 22, 2022, 2:22:22 AM"
twosday.formatted(.dateTime.second().minute().hour().day().month().year()) // "Feb 22, 2022, 2:22:22 AM"

// MARK: - Formatting Individual Components

twosday.formatted(.dateTime.day(.twoDigits))            // "22"
twosday.formatted(.dateTime.day(.ordinalOfDayInMonth))  // "4"
twosday.formatted(.dateTime.day(.defaultDigits))        // "22"

// MARK: - Custom Date.FormatStyle

let posixStyle = Date.FormatStyle(
    date: .complete,
    time: .complete,
    locale: Locale(identifier: "en_us_POSIX"),
    calendar: Calendar(identifier: .chinese),
    timeZone: TimeZone(secondsFromGMT: 0)!,
    capitalizationContext: .standalone
)

twosday.formatted(posixStyle) // "Tuesday, February 22, 2022(2022), 9:22:22 AM GMT"

// MARK: - Custom FormatStyle

/// Returns the date in the most useless way ever
struct ReversedDateFormat: FormatStyle {
    typealias FormatInput = Date
    typealias FormatOutput = String

    func format(_ value: Date) -> String {
        "\(value.formatted(.dateTime.second())):" +
            "\(value.formatted(.dateTime.minute())):" +
            "\(value.formatted(.dateTime.hour())) " +
            "\(value.formatted(.dateTime.day())) " +
            "\(value.formatted(.dateTime.month())) " +
            "\(value.formatted(.dateTime.year())) "
    }
}

extension FormatStyle where Self == ReversedDateFormat {
    static var reversedDate: ReversedDateFormat { .init() }
}

twosday.formatted(.reversedDate) // "22:22:2 AM 22 Feb 2022"