Type Alias $<T, $O>

$: $Distributive.Parse<
    $O,
    {
        $else: [T] extends [readonly any[]]
            ? number extends T["length"]
                ? $ResolveBranch<$O, [$Else]>
                : $ResolveBranch<$O, [$Then], T>
            : $ResolveBranch<$O, [$Else]>;
        $then: T extends readonly any[]
            ? number extends T["length"]
                ? $ResolveBranch<$O, [$Else]>
                : $ResolveBranch<$O, [$Then], T>
            : $ResolveBranch<$O, [$Else]>;
    },
>