Handling UIFont in swift

TypeFace.swift

//custom-dynamic-type.swift
protocol CustomDynamicTypeable {
    func preferredFont(forTextStyle style: UIFontTextStyle) -> UIFont?
    func font(forSize pointSize: CGFloat) -> UIFont?
}

// judson-enum.swift
enum JudsonFont: String, CustomDynamicTypeable {
    case regular = "Judson-Regular"
    case bold    = "Judson-Bold"
}


// dynamic-type-extension-raw-representable.swift
extension CustomDynamicTypeable where Self: RawRepresentable, Self.RawValue == String {
    func preferredFont(forTextStyle style: UIFontTextStyle) -> UIFont? {
        let font = UIFont.preferredFont(forTextStyle: style)
        return UIFont(name: rawValue, size: font.pointSize)
    }
    
    func font(forSize pointSize: CGFloat) -> UIFont? {
        return UIFont(name: rawValue, size: pointSize)
    }
}

// usage
let font = JudsonFont.regular.preferredFont(forTextStyle: .body)