Date extension to get pretty Apple-mail like labels.

Date.swift

import Foundation

extension Date {
    
    func formattedMessageDate() -> String {
        
        let startOfToday = Calendar.current.startOfDay(for: Date())
        
        let startOfDate = Calendar.current.startOfDay(for: self)
        
        let components = (Calendar.current as NSCalendar).components([NSCalendar.Unit.day, NSCalendar.Unit.hour], from: startOfDate, to: startOfToday, options: NSCalendar.Options(rawValue: 0))
        
        if components.day! > 7 {
            return self.shortDate
        } else if components.day == 0 {
            return self.time
        } else if components.day == 1 {
            return "Yesterday"
        } else {
            return self.weekdayString()
        }
    }
    
    var shortDate: String {
        
        let dateFormatter = DateFormatter()
        dateFormatter.dateStyle = .short
        return dateFormatter.string(from: self)
    }
    
    var weekday: String {
        
        let weekdayFormatter = DateFormatter()
        weekdayFormatter.dateFormat = "EEEE"
        return weekdayFormatter.string(from: self)
    }
    
    func weekdayString() -> String {
        
        let weekdayFormatter = DateFormatter()
        weekdayFormatter.dateFormat = "EEEE"
        return weekdayFormatter.string(from: self)
    }
    
    var time: String {
        
        let weekdayFormatter = DateFormatter()
        weekdayFormatter.dateFormat = "HH:mm"
        weekdayFormatter.timeStyle = .short
        return weekdayFormatter.string(from: self)
    }
    
    static func testDate(_ daysAgo: Int) -> Date {
        
        let testDate = "2016-01-17 17:39:48"
        
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "YYYY-MM-dd HH:mm:ss"
        
        if let date = dateFormatter.date(from: testDate) {
            var components = (Calendar.current as NSCalendar).components([NSCalendar.Unit.year,
                                                                          NSCalendar.Unit.day,
                                                                          NSCalendar.Unit.hour],
                                                                         from: date)
           
            guard let day = components.day else {
                return Date()
            }
            
            components.day = day - daysAgo
            let yesterday = Calendar.current.date(from: components)
            
            return yesterday ?? Date()
        }
        
        return Date()
    }
}