Optional arguments about quickjspp

[ftk]

Good idea!

[ftk]

Another idea is to create a specialization for std::optional

template <typename T, size_t I, size_t NArgs>
struct unwrap_arg_impl<std::optional<T>, I, NArgs> {
    static std::optional<T> unwrap(JSContext * ctx, int argc, JSValueConst * argv) {
         if (size_t(argc) <= I) return std::nullopt;
        return {js_traits<std::decay_t<T>>::unwrap(ctx, argv[I])};
    }
};