Swift EnumMap

EnumMap.swift

enum TextType: CaseIterable {
    case title
    case subtitle
    case sectionTitle
    case body
    case comment
}


struct EnumMap<Enum: CaseIterable & Hashable, Value> {
    private let values: [Enum : Value]

    init(resolver: (Enum) -> Value) {
        var values = [Enum : Value]()

        for key in Enum.allCases {
            values[key] = resolver(key)
        }

        self.values = values
    }

    subscript(key: Enum) -> Value {
        return values[key]!
    }
}

let fonts = EnumMap<TextType, UIFont> { type in
    switch type {
    case .title:
        return .preferredFont(forTextStyle: .headline)
    case .subtitle:
        return .preferredFont(forTextStyle: .subheadline)
    case .sectionTitle:
        return .preferredFont(forTextStyle: .title2)
    case .body:
        return .preferredFont(forTextStyle: .body)
    case .comment:
        return .preferredFont(forTextStyle: .footnote)
    }
}


let titleFont = fonts[.title]
print(titleFont)