Swift 3 Monospaced UIFont Extension

monospaced.swift

//  monospaced extension
//  usage: object.font = object.font.monospacedDigitFont

import UIKit

extension UIFont {
    
    var monospacedDigitFont: UIFont {
        let oldFontDescriptor = fontDescriptor
        let newFontDescriptor = oldFontDescriptor.monospacedDigitFontDescriptor
        return UIFont(descriptor: newFontDescriptor, size: 0)
    }
    
}

private extension UIFontDescriptor {
    
    var monospacedDigitFontDescriptor: UIFontDescriptor {
        let fontDescriptorFeatureSettings = [[UIFontFeatureTypeIdentifierKey: kNumberSpacingType, UIFontFeatureSelectorIdentifierKey: kMonospacedNumbersSelector]]
        let fontDescriptorAttributes = [UIFontDescriptorFeatureSettingsAttribute: fontDescriptorFeatureSettings]
        let fontDescriptor = self.addingAttributes(fontDescriptorAttributes)
        return fontDescriptor
    }
    
}