Time

Time is a Swift package that makes dealing with calendar values a natural and straight-forward process.

Working with calendars can be extremely complicated and error-prone. Time solves these problems by clarifying concepts and restricting improper usage through type-safe APIs.

Installing

Time can be installed like any other Swift package. Add this to the dependencies section of your Package.swift:

.package(url: "https://github.com/davedelong/time", from: "0.9.1")

The Basics

Here's the TL;DR of the documentation:

If you want to know what time it is, you need a Clock. You can get the device's clock by using Clocks.system.
A Clock can tell you the current time via some functions. For example, .today() will give you the current calendar day. .thisMinute() will give you the current time, accurate down to the minute level.
Each of these returned values has methods to retrieve more- and less- precise values. For example, today.hours() will give you a sequence of all the "Hour" values in the day.
These values also are how you format them into human-readable strings (via the .format(...) method)

Some Small Examples

There are some examples below showing a sneak peek of what you can do with Time.

Fetching the Current Time

let clock = Clocks.system

// retrieve the current instantaneous time from the clock
let now = clock.thisInstant()

// retrieve the current calendar day, as defined by the user's region
let today = clock.today()

More information in "Clock".

Converting Between Regions

let nycTimeZone = TimeZone(identifier: "America/New_York")!

let myClock = Clocks.system
let nycClock = myClock.converting(to: nycTimeZone)

let myLocalTime = myClock.thisMinute() // Ex: 28 Feb 2020 at 3:14 PM Pacific Time

let nycLocalTime = nycClock.thisMinute() // Ex: 28 Feb 2020 at 6:14 PM Eastern Time

More information in "Clock".

Retrieving Components

let today: Absolute<Day> = myClock.today()
let year = today.year // Ex: 2020
let month = today.month // Ex: 2
let day = today.day // Ex: 28

More information in "TimePeriod".

Calculating Differences

let day1: Absolute<Day> = ...
let day2: Absolute<Day> = ...

// compute the difference in days, months, years, and eras
let difference: TimeDifference<Day, Era> = day1.difference(to: day2)

// or conveniently the number of calendar days between the two values
let daysDifference = day1.differenceInDays(to: day2)

More information in "Differences".

Iterating Over TimePeriods

let thisMonth = Clocks.system.thisMonth()
let daysInThisMonth = thisMonth.days()

for day in daysInThisMonth {
    // …
}

More information in "Iterating Over TimePeriods".

Formatting TimePeriods

let today: Absolute<Day> = ...

let fullYearString = today.format(date: .full) // Ex: February 28, 2020
let shortYearString = today.format(year: .twoDigits, month: .full) // Ex: February '20

More information in "Formatting TimePeriods".

Observing time changes

let clock: Clock = ...
clock
    .chime(every: .seconds(5))
    .sink { (value: Absolute<Second>) in
        print("Another 5 seconds have passed")
    }
    .store(in: &cancellables)

More information in "Observing time changes".

Detailed Information

For more information, please see the documentation.

Mordil/time