Type Alias _N<T, $O>

_N: [T] extends [boolean]
    ? [T] extends [true]
        ? $ResolveBranch<$O, [$Else]>
        : [T] extends [false]
            ? $ResolveBranch<$O, [$Else]>
            : $ResolveBranch<$O, [$Then], T>
    : $ResolveBranch<$O, [$Else]>