A Swift Date extension helper

DateHelper

A Swift Date extension for iOS, watchOS, tvOS, and macOS that creates or converts dates to or from strings. It can also compare, modify or extract date components and uses cached formatters for performance gains.

Capabilities

Convert from string

date = Date(fromString: "2009-08-11", format: .isoDate)

Convert to string

let mediumDateString = date.toString(style: .medium)
let rssDateString = date.toString(format: .rss)
let shortTimeString =  date.toString(dateStyle: .none, timeStyle: .short)
let relativeTimeSting = date.toStringWithRelativeTime()

Compare dates

let isToday = date.compare(.isToday)
let isSameWeek = date.compare(.isSameWeek(as: otherDate))

Adjust dates

let twoHoursBefore = date.adjust(.hour, offset: -2)
let atNoon = date.adjust(hour: 12, minute: 0, second: 0)

Create dates for...

let startOfWeek = date.dateFor(.startOfWeek)
let nearest5Hours = date.dateFor(.nearestHour(hour:5))

Forcing a week to start on monday

var calendar = Calendar(identifier: .gregorian)
calendar = 2 // sets the week to start on the second day.. monday
now.dateFor(.startOfWeek, calendar: calendar)

Time since...

let secondsSince = date.since(otherDate, in: .second)

Extracting components

let seconds = date.component(.second)
let daysInMonth = date.numberOfDaysInMonth()
let firstDayOfWeek = date.firstDayOfWeek()
let lastDayOfWeek = date.lastDayOfWeek()

Usage

Date from string

Use the initializer Date(fromString:String, format: DateFormatType)? to create an optional date from a string.

if let date = Date(fromString: "09 Sep 2011 15:26:08 +0200", format: .httpHeader) -> 
 {
	// Do stuff with date
}

The DateFormatType enum has a few predifined options as well as a tupple for providing a custom date format.

case isoYear: i.e. 1997
case isoYearMonth: i.e. 1997-07
case isoDate: i.e. 1997-07-16
case isoDateTime: i.e. 1997-07-16T19:20+01:00
case isoDateTimeSec: i.e. 1997-07-16T19:20:30+01:00
case isoDateTimeMilliSec: i.e. 1997-07-16T19:20:30.45+01:00
case dotNet: i.e. "/Date(1268123281843)/"
case rss: i.e. "Fri, 09 Sep 2011 15:26:08 +0200"
case altRSS: i.e. "09 Sep 2011 15:26:08 +0200"
case httpHeader: i.e. "Tue, 15 Nov 1994 12:45:26 GMT"
case standard: "EEE MMM dd HH:mm:ss Z yyyy"
case custom(String): a custom date format string

To String

There's four options for converting a date to string.

1. date.toString(style: .shortWeekday)
2. date.toString(format: .rss)
3. date.toString(dateStyle: .short, timeStyle: .short)
4. date.toStringWithRelativeTime()

1. String with style

Converts to string using a predefined style

let string = date.toString(.shortWeekday)
// Mon

The DateStyleType enum

case short; "2/27/17, 2:22 PM"
case medium; "Feb 27, 2017, 2:22:06 PM"
case long; "February 27, 2017 at 2:22:06 PM EST"
case full; "Monday, February 27, 2017 at 2:22:06 PM Eastern Standard Time"
case ordinalDay; 27th
case weekday; "Monday"
case shortWeekday; "Mon"
case veryShortWeekday; "M"
case month; "February"
case shortMonth; "Feb"
case veryShortMonth; "F"

2. String with format

Converts to string with specific or custom date formatters.

let string = date.toString(format: .rss)
// Fri, 09 Sep 2011 15:26:08 +0200

The DateFormatType enum has a few predifined options as well as a tupple for providing a custom date format.

case isoYear: i.e. 1997
case isoYearMonth: i.e. 1997-07
case isoDate: i.e. 1997-07-16
case isoDateTime: i.e. 1997-07-16T19:20+01:00
case isoDateTimeSec: i.e. 1997-07-16T19:20:30+01:00
case isoDateTimeMilliSec: i.e. 1997-07-16T19:20:30.45+01:00
case dotNet: i.e. "/Date(1268123281843)/"
case rss: i.e. "Fri, 09 Sep 2011 15:26:08 +0200"
case altRSS: i.e. "09 Sep 2011 15:26:08 +0200"
case httpHeader: i.e. "Tue, 15 Nov 1994 12:45:26 GMT"
case standard: "EEE MMM dd HH:mm:ss Z yyyy"
case custom(String): a custom date format string

Unicode Date Field Symbol Guide

3. String with date and time style

Converts to string using a DateFormatter.Style for date and time style plus an optional isRelative flag.

let string = date.toString(dateStyle: .short, timeStyle: .short)
// 11/23/37 3:30 PM

The DateFormatter.Style uses predefined formats for date and time.

case .none
case .short; "11/23/37" or "3:30 PM"
case .medium; "Nov 23, 1937" or "3:30:32 PM"
case .long; "November 23, 1937" or "3:30:32 PM PST"
case .full; "Tuesday, April 12, 1952 AD" or "3:30:42 PM Pacific Standard Time"

4. String with relative time format

Converts to string using a customizable relative time format.

let string = date.toStringWithRelativeTime()
// yesterday

Use the optional strings:[RelativeTimeStringType:String]? to customize the relative time strings

let string = date.toStringWithRelativeTime([.nowPast: "just posted"])

The RelativeTimeStringType enum keys are used for customizing the strings

case nowPast: "just now"
case nowFuture: "in a few seconds"
case secondsPast: "%.f seconds ago"
case secondsFuture: "in %.f seconds"
case oneMinutePast: "1 minute ago"
case oneMinuteFuture: "in 1 minute"
case minutesPast: "%.f minutes ago"
case minutesFuture: "in %.f minutes"
case oneHourPast: "last hour"
case oneHourFuture: "next hour"
case hoursPast: "%.f hours ago"
case hoursFuture: "in %.f hours"
case oneDayPast: "yesterday"
case oneDayFuture: "tomorrow"
case daysPast: "%.f days ago"
case daysFuture: "in %.f days"
case oneWeekPast: "last week"
case oneWeekFuture: "next week"
case weeksPast: "%.f weeks ago"
case weeksFuture: "in %.f weeks"
case oneMonthPast: "last month"
case oneMonthFuture: "next month"
case monthsPast: "%.f months ago"
case monthsFuture: "in %.f months"
case oneYearPast: "last year"
case oneYearFuture: "next year"
case yearsPast: "%.f years ago"
case yearsFuture: "in %.f years"

Comparing Dates

Use the compare(_ comparison:DateComparisonType) -> Bool function to compare a date against a type or a date.

var isSameDay = now.compare(.isSameDay(as: date))
var isToday = now.compare(.isToday)  

The DateComparisonType enum can compare the date to a predetermined date, period or a custom date in a tupple. i.e. isLater(thanDate:Date)

// Days
case isToday
case isTomorrow
case isYesterday
case isSameDay(as:Date)
// Weeks
case isThisWeek
case isNextWeek
case isLastWeek
case isSameWeek(as:Date)
// Months
case isThisMonth
case isNextMonth
case isLastMonth
case isSameMonth(as:Date)
// Years
case isThisYear
case isNextYear
case isLastYear
case isSameYear(as:Date)
// Relative Time
case isInTheFuture
case isInThePast
case isEarlier(than:Date)
case isLater(than:Date)
case isWeekday
case isWeekend

Adjusting Dates

Use the adjust(_ component:DateComponentType, offset:Int) -> Date to change a the date with an offset.

date = now.adjust(.day, offset: -4)

The DateComponentType enum is used for the components that can be adjusted.

case second
case minute
case hour
case day
case weekday
case nthWeekday
case week
case month
case year

Use the adjust(hour: Int?, minute: Int?, second: Int?, day: Int? = nil, month: Int? = nil) -> Date function to change the date components.

let atNoon = date.adjust(hour: 12, minute: 0, second: 0)

Create Dates For...

Use the dateFor(_ type:DateForType) -> Date function to create a new date for a specific occasion relative to the date.

let date = now.dateFor(.startOfWeek)
let nearestHour = now.dateFor(.nearestHour(hour:1))

The DateForType enum is used as a predetermined list of options.

case startOfDay
case endOfDay
case startOfWeek
case endOfWeek
case startOfMonth
case endOfMonth
case tomorrow
case yesterday
case nearestHour
case nearestMinute(minute:Int)
case nearestHour(hour:Int)

Time Since In...

Use the since(_ date:Date, in component:DateComponentType) -> Int64 function to retrieve the component interval value compared to another date.

var num = date.since(now, in: .second)

The DateComponentType enum is used for the vlaue to be retrieved.

case second
case minute
case hour
case day
case weekday
case nthWeekday
case week
case month
case year

Extracting Components

Use the component(_ component:DateComponentType) -> Int? to get a specific component froma date.

let minute = date.component(.minute) 

The DateComponentType enum is used for the vlaue to be retrieved.

case second
case minute
case hour
case day
case weekday
case nthWeekday
case week
case month
case year

Related components to the date

date.numberOfDaysInMonth()
date.firstDayOfWeek()
date.lastDayofWeek()

Requirements

Language: Swift 4.0
Minimum: iOS 9, tvOS 9, watchOS 2, macOS 10.06

Installation

Carthage github "melvitax/DateHelper"
Cocoapods pod 'AFDateHelper', '~> 4.2.2'
Manually Include DateHelper.swift in your project

Author

Melvin Rivera

GitHub