Determining if Swift dictionary contains key and obtaining any of its values

Question

I am currently using the following (clumsy) pieces of code for determining if a (non-empty) Swift dictionary contains a given key and for obtaining one (any) value from the

Answer 1

My solution for a cache implementation that stores optional NSAttributedString:

public static var attributedMessageTextCache    = [String: NSAttributedString?]()

    if attributedMessageTextCache.index(forKey: "key") != nil
    {
        if let attributedMessageText = TextChatCache.attributedMessageTextCache["key"]
        {
            return attributedMessageText
        }
        return nil
    }

    TextChatCache.attributedMessageTextCache["key"] = .some(.none)
    return nil