Date Extension

Compare.m

- (NSComparisonResult)compareDatesWith:(NSDate*)otherDate {
     NSCalendar* calendar = [NSCalendar currentCalendar];
     
     unsigned unitFlags = NSCalendarUnitYear | NSCalendarUnitMonth |  NSCalendarUnitDay;
     NSDateComponents* comp1 = [calendar components:unitFlags fromDate:self];
     NSDateComponents* comp2 = [calendar components:unitFlags fromDate:otherDate];
     NSInteger comparison = [comp1 year] * 10000 + [comp1 month] * 100 + [comp1 day] -
             ([comp2 year] * 10000 + [comp2 month] * 100 + [comp2 day]);
     
     return comparison > 0 ? NSOrderedDescending : comparison < 0 ? NSOrderedAscending :      NSOrderedSame;
 }

Date+Format.swift

extension Date {
    func toString(format: String) -> String {
        let formatter = DateFormatter()
        formatter.dateFormat = format
        return formatter.string(from: self)
    }
    
    var isToday: Bool {
        return compareDate(Date()) == .orderedSame
    }
    
    var isYesterday: Bool {
        let yesterday = Date().addDay(-1)
        return compareDate(yesterday) == .orderedSame
    }
    
    var toUserFriendlyFormat: String {
        switch self {
        case let date where date.isToday:
            return "Today"
        case let date where date.isYesterday:
            return "Yesterday"
        default:
            return self.toString(format: "dd MMMM")
        }
    }
    
    private func addDay(_ diff: Int) -> Date {
        let calendar = Calendar.current
        return calendar.date(byAdding: .day, value: diff, to: self)!
    }
    
    private func compareDate(_ other: Date) -> ComparisonResult {
        let calendar = Calendar.current
        
        let components: [Calendar.Component] = [.year, .month, .day]
        let lhs = calendar.dateComponents(Set(components), from: self)
        let rhs = calendar.dateComponents(Set(components), from: other)
        let diff = (lhs.year! - rhs.year!) * 10000 + (lhs.month! - rhs.month!) * 100 + lhs.day! - rhs.day!
        
        return diff > 0 ? .orderedAscending : diff == 0 ? .orderedSame : .orderedDescending
    }
}