_ApplyDefaultOptions

type _ApplyDefaultOptions<Options, Defaults, SpecifiedOptions> =
    If<
        IsAny<SpecifiedOptions>,
        Defaults,
        If<
            IsNever<SpecifiedOptions>,
            Defaults,
            Merge<
                Defaults,
                {
                    [Key in keyof SpecifiedOptions as undefined extends Required<Options>[Key &
                        keyof Options]
                        ? Key
                        : undefined extends SpecifiedOptions[Key]
                          ? never
                          : Key]: SpecifiedOptions[Key];
                }
            >
        >
    >;

type _ApplyDefaultOptions<Options, Defaults, SpecifiedOptions> =
    If<
        IsAny<SpecifiedOptions>,
        Defaults,
        If<
            IsNever<SpecifiedOptions>,
            Defaults,
            Merge<
                Defaults,
                {
                    [Key in keyof SpecifiedOptions as undefined extends Required<Options>[Key &
                        keyof Options]
                        ? Key
                        : undefined extends SpecifiedOptions[Key]
                          ? never
                          : Key]: SpecifiedOptions[Key];
                }
            >
        >
    >;