isToday var for Date struct

Date+Today.swift

extension Date {
    
    var isToday : Bool {
        let cal = Calendar.current
        var components = cal.dateComponents([.era, .year, .month, .day], from: Date())
        let today = cal.date(from: components)!
        components = cal.dateComponents([.era, .year, .month, .day], from: self)
        let thisDate = cal.date(from: components)!
        return (today as NSDate).isEqual(to: thisDate)
    }
    
}