Swift Date Functions

Date+Extension.swift

//
//  Date+Extension.swift
//
//  Created by Alexandre Giguere on 2016-05-16.
//

import Foundation

extension Date {

    public init?(jsonDate: String) {
        if jsonDate.count == 26 {
            let timeStamp = jsonDate[jsonDate.index(jsonDate.startIndex, offsetBy: 6)..<jsonDate.index(jsonDate.endIndex, offsetBy: -7)]
            
            if let timeInterval = Double(timeStamp) {
                self.init(timeIntervalSince1970: (timeInterval / 1000.0))
            } else {
                return nil
            }
            
        } else if jsonDate.count == 21 {
            let timeStamp = jsonDate[jsonDate.index(jsonDate.startIndex, offsetBy: 6)..<jsonDate.index(jsonDate.endIndex, offsetBy: -2)]
            
            if let timeInterval = Double(timeStamp) {
                self.init(timeIntervalSince1970: (timeInterval / 1000.0))
            } else {
                return nil
            }
            
        } else {
            return nil
        }
    }
    
    public var jsonString: String {
        let time = Int64(self.timeIntervalSince1970 * 1000.0)
        return "/Date(\(time)+0000)/"
    }
    
    public static func today12AM() -> Date {
        let calendar = Calendar(identifier: Calendar.Identifier.gregorian)
        
        let currentDateComponents = calendar.dateComponents([.year, .month, .day], from: Date())
        
        return calendar.date(from: currentDateComponents)!
    }
    
    public mutating func setTimeTo12AM() {
        let calendar = Calendar(identifier: Calendar.Identifier.gregorian)
        
        let currentDateComponents = calendar.dateComponents([.year, .month, .day], from: self)
        
        self = calendar.date(from: currentDateComponents)!
    }
    
    public func settingTimeTo12AM() -> Date {
        let calendar = Calendar(identifier: Calendar.Identifier.gregorian)
        
        let currentDateComponents = calendar.dateComponents([.year, .month, .day], from: self)
        
        return calendar.date(from: currentDateComponents)!
    }
    
    // Returns the amount of years from another date
    public func years(from date: Date) -> Int {
        return Calendar.current.dateComponents([.year], from: date, to: self).year ?? 0
    }
    
    // Returns the amount of months from another date
    public func months(from date: Date) -> Int {
        return Calendar.current.dateComponents([.month], from: date, to: self).month ?? 0
    }
    
    // Returns the amount of weeks from another date
    public func weeks(from date: Date) -> Int {
        return Calendar.current.dateComponents([.weekOfYear], from: date, to: self).weekOfYear ?? 0
    }
    
    // Returns the amount of days from another date
    public func days(from date: Date) -> Int {
        return Calendar.current.dateComponents([.day], from: date, to: self).day ?? 0
    }
    
    // Returns the amount of hours from another date
    public func hours(from date: Date) -> Int {
        return Calendar.current.dateComponents([.hour], from: date, to: self).hour ?? 0
    }
    
    // Returns the amount of minutes from another date
    public func minutes(from date: Date) -> Int {
        return Calendar.current.dateComponents([.minute], from: date, to: self).minute ?? 0
    }
    
    // Returns the amount of seconds from another date
    public func seconds(from date: Date) -> Int {
        return Calendar.current.dateComponents([.second], from: date, to: self).second ?? 0
    }
}