Swift Date Helpers

Date.playground

// Playground - noun: a place where people can play

import UIKit

var str = "Hello, playground"

enum TimeIntervalUnit {
  case Seconds, Minutes, Hours, Days, Months, Years
  
  func dateComponents(interval: Int) -> NSDateComponents {
    var components:NSDateComponents = NSDateComponents()

    switch (self) {
      case .Seconds:
        components.second = interval
      case .Minutes:
        components.minute = interval
      case .Days:
        components.day = interval
      case .Months:
        components.month = interval
      case .Years:
        components.year = interval
      default:
        components.day = interval
    }
    return components
  }
}

struct TimeInterval {
  var interval: Int
  var unit: TimeIntervalUnit
  
  var ago: NSDate {
    var calendar = NSCalendar.currentCalendar()
    let today = NSDate.date()
    var components = unit.dateComponents(-self.interval)
    return calendar.dateByAddingComponents(components, toDate: today!, options: nil)
  }
  
  init(interval: Int, unit: TimeIntervalUnit) {
    self.interval = interval
    self.unit = unit
  }
}

var a = TimeInterval(interval: 10, unit: TimeIntervalUnit.Months)

extension Int {
  var seconds: TimeInterval {
    return TimeInterval(interval: self, unit: TimeIntervalUnit.Seconds)
  }
  var minutes: TimeInterval {
    return TimeInterval(interval: self, unit: TimeIntervalUnit.Minutes)
  }
  var days: TimeInterval {
    return TimeInterval(interval: self, unit: TimeIntervalUnit.Days)
  }
  var months: TimeInterval {
    return TimeInterval(interval: self, unit: TimeIntervalUnit.Months);
  }
  var years: TimeInterval {
    return TimeInterval(interval: self, unit: TimeIntervalUnit.Years)
  }
}

@infix func - (let left:NSDate, let right:TimeInterval) -> NSDate {
  var calendar = NSCalendar.currentCalendar()
  var components = right.unit.dateComponents(-right.interval)
  return calendar.dateByAddingComponents(components, toDate: left, options: nil)
}

@infix func + (let left:NSDate, let right:TimeInterval) -> NSDate {
  var calendar = NSCalendar.currentCalendar()
  var components = right.unit.dateComponents(right.interval)
  return calendar.dateByAddingComponents(components, toDate: left, options: nil)
}

var test1 = 2.years.ago
var test2 = NSDate.date() - 4.days
var test3 = NSDate.date() + 5.months

@infix func < (let left:NSDate, let right: NSDate) -> Bool {
  var result:NSComparisonResult = left.compare(right)
  var isEarlier = false
  if (result == NSComparisonResult.OrderedAscending) {
    isEarlier = true
  }
  return isEarlier
}

@infix func > (let left:NSDate, let right: NSDate) -> Bool {
  var result:NSComparisonResult = left.compare(right)
  var isLater = false
  if (result == NSComparisonResult.OrderedDescending) {
    isLater = true
  }
  return isLater
}

@infix func == (let left:NSDate, let right: NSDate) -> Bool {
  var result:NSComparisonResult = left.compare(right)
  var isEqual = false
  if (result == NSComparisonResult.OrderedSame) {
    isEqual = true
  }
  return isEqual
}

var test4 = test2 < test3
var test5 = test3 > test1
var test6 = NSDate.date() == test1

extension NSDate {
  class func yesterday() -> NSDate {
    return NSDate.date() - 1.days
  }
  
  func toS(let format:String) -> String? {
    var formatter:NSDateFormatter = NSDateFormatter()
    formatter.locale = NSLocale(localeIdentifier: "en_US_POSIX")
    formatter.timeZone = NSTimeZone()
    formatter.dateFormat = format
    
    return formatter.stringFromDate(self)
  }
}

var test7 = NSDate.yesterday().toS("MM/dd")

extension String {
  
  func toDate(let format:String = "dd/MM/yyyy") -> NSDate? {
    var formatter:NSDateFormatter = NSDateFormatter()
    formatter.locale = NSLocale(localeIdentifier: "en_US_POSIX")
    formatter.timeZone = NSTimeZone()
    formatter.dateFormat = format
    
    return formatter.dateFromString(self)
  }
}

var test8 = "12/01/2014".toDate(format: "MM/dd/yyyy")
var test9 = "12/01/2014".toDate()

Updated to Swift 2.1.1

// Playground - noun: a place where people can play

import UIKit

// XCode Version 7.2.1 (7C1002)
// Apple Swift version 2.1.1 (swiftlang-700.1.101.15 clang-700.1.81)

enum TimeIntervalUnit {
case Seconds, Minutes, Hours, Days, Months, Years

func dateComponents(interval: Int) -> NSDateComponents {
    let components:NSDateComponents = NSDateComponents()

    switch (self) {
    case .Seconds:
        components.second = interval
    case .Minutes:
        components.minute = interval
    case .Days:
        components.day = interval
    case .Months:
        components.month = interval
    case .Years:
        components.year = interval
    default:
        components.day = interval
    }
    return components
}

}

struct TimeInterval {
var interval: Int
var unit: TimeIntervalUnit

var ago: NSDate {
    let calendar = NSCalendar.currentCalendar()
    let today = NSDate()
    let components = unit.dateComponents(-self.interval)
    return calendar.dateByAddingComponents(components, toDate: today, options: NSCalendarOptions(rawValue: 0))!
}

init(interval: Int, unit: TimeIntervalUnit) {
    self.interval = interval
    self.unit = unit
}

}

var a = TimeInterval(interval: 10, unit: TimeIntervalUnit.Months)

extension Int {
var seconds: TimeInterval {
return TimeInterval(interval: self, unit: TimeIntervalUnit.Seconds)
}
var minutes: TimeInterval {
return TimeInterval(interval: self, unit: TimeIntervalUnit.Minutes)
}
var days: TimeInterval {
return TimeInterval(interval: self, unit: TimeIntervalUnit.Days)
}
var months: TimeInterval {
return TimeInterval(interval: self, unit: TimeIntervalUnit.Months);
}
var years: TimeInterval {
return TimeInterval(interval: self, unit: TimeIntervalUnit.Years)
}
}

func - (let left:NSDate, let right:TimeInterval) -> NSDate {
let calendar = NSCalendar.currentCalendar()
let components = right.unit.dateComponents(-right.interval)
return calendar.dateByAddingComponents(components, toDate: left, options: NSCalendarOptions(rawValue: 0))!
}

func + (let left:NSDate, let right:TimeInterval) -> NSDate {
let calendar = NSCalendar.currentCalendar()
let components = right.unit.dateComponents(right.interval)
return calendar.dateByAddingComponents(components, toDate: left, options: NSCalendarOptions(rawValue: 0))!
}

var test1 = 2.years.ago
var test2 = NSDate() - 4.days
var test3 = NSDate() + 5.months

func < (let left:NSDate, let right: NSDate) -> Bool {
let result:NSComparisonResult = left.compare(right)
var isEarlier = false
if (result == NSComparisonResult.OrderedAscending) {
isEarlier = true
}
return isEarlier
}

func > (let left:NSDate, let right: NSDate) -> Bool {
let result:NSComparisonResult = left.compare(right)
var isLater = false
if (result == NSComparisonResult.OrderedDescending) {
isLater = true
}
return isLater
}

func == (let left:NSDate, let right: NSDate) -> Bool {
let result:NSComparisonResult = left.compare(right)
var isEqual = false
if (result == NSComparisonResult.OrderedSame) {
isEqual = true
}
return isEqual
}

var test4 = test2 < test3
var test5 = test3 > test1
var test6 = NSDate() == test1

extension NSDate {
class func yesterday() -> NSDate {
return NSDate() - 1.days
}

func toS(let format:String) -> String? {
    let formatter:NSDateFormatter = NSDateFormatter()
    formatter.locale = NSLocale(localeIdentifier: "en_US_POSIX")
    formatter.timeZone = NSTimeZone()
    formatter.dateFormat = format

    return formatter.stringFromDate(self)
}

}

var test7 = NSDate.yesterday().toS("MM/dd")

extension String {

func toDate(let format:String = "dd/MM/yyyy") -> NSDate? {
    let formatter:NSDateFormatter = NSDateFormatter()
    formatter.locale = NSLocale(localeIdentifier: "en_US_POSIX")
    formatter.timeZone = NSTimeZone()
    formatter.dateFormat = format

    return formatter.dateFromString(self)
}

}

var test8 = "12/01/2014".toDate("MM/dd/yyyy")
var test9 = "12/01/2014".toDate()