extends TimeInterval with durationString that returns a human readable duration in decimal or time format (HH:MM:SS)

TimeInterval-extension.swift

extension TimeInterval {
    func durationString(_ decimal: Bool) -> String {
        if decimal {
            let formatter = NumberFormatter()
            formatter.minimumFractionDigits = 2
            formatter.maximumFractionDigits = 2
            formatter.minimumIntegerDigits = 1
            let a = self / 3600
            return formatter.string(from: NSNumber(value: a))! + " h"
            
        } else {
            let formatter = NumberFormatter()
            formatter.minimumIntegerDigits = 2
            formatter.maximumIntegerDigits = 2
            let ti = Int(self)
            
            let seconds = ti % 60
            let minutes = (ti / 60) % 60
            let hours = (ti / 3600)
            
            return "\(formatter.string(from: NSNumber(value: hours))!):\(formatter.string(from: NSNumber(value: minutes))!):\(formatter.string(from: NSNumber(value: seconds))!)"
        }
    }
    
    var dateString : String {
        if self > 0 {
            let date = Date(timeIntervalSince1970: self)
            let formatter = DateFormatter()
            formatter.timeStyle = .short
            formatter.dateStyle = .short
            return formatter.string(from: date)
        } else {
            return "---"
        }
    }
}