Font Extension for Monospaced Digits (Swift 4.0)

Font+MonospacedDigits.swift

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 = [[UIFontDescriptor.FeatureKey.featureIdentifier: kNumberSpacingType, UIFontDescriptor.FeatureKey.typeIdentifier: kMonospacedNumbersSelector]]
		let fontDescriptorAttributes = [UIFontDescriptor.AttributeName.featureSettings: fontDescriptorFeatureSettings]
		let fontDescriptor = self.addingAttributes(fontDescriptorAttributes)
		return fontDescriptor
	}
}