Let’s take a simple example:

type filePath = Opaque<...>;

function isFile(path: string, stats: Stats): path is filePath {
  return stats.isFile();
}

Works great. Now I’m trying to make that function async:

function isFile(path: string): Promise<path is filePath> {
    const stats = await stat(path);
    return stat.isFile();
}

However typescript doesn’t even like the syntax there and absolutely chokes on Promise<path is filePath>. Is there a way to get a type predicate into a promise?

obligatory ts playground link