Optimizing Authentication and Authorization in TypeScript

class JwtError {
  readonly _tag = "JwtError";
}

class UserConnectionError {
  readonly _tag = "UserConnectionError";
}

type JwtPayload = { id: number; name: string; time: number; iat: number };

const auth = async (pathname: string, user: string | undefined) => {
  if (!pathname.startsWith("/admin")) return true;
  if (pathname.startsWith("/admin/login")) return true;
  if (!user) return false;

  const jwtVerification = Effect.try({
    try: () => jwt.verify(user, process.env.JWT_SECRET!) as JwtPayload,
    catch: () => new JwtError(),
  });

  const checkUserExists = (id: number, name: string) => {
    return Effect.tryPromise({
      try: async () => {
        const res = await pg
          .select({ count: sql<number>`count(*)` })
          .from(users)
          .where(and(eq(users.id, id), eq(users.name, name)));
        return res[0].count > 0;
      },
      catch: () => new UserConnectionError(),
    });
  };

  const program = pipe(
    jwtVerification,
    Effect.flatMap(({ id, name }) => checkUserExists(id, name)),
  );

  const handling = Effect.match(program, {
    onSuccess: (x) => x,
    onFailure(error) {
      if (error._tag === "UserConnectionError") {
        console.log(`Error: ${error._tag}`);
      }
      return false;
    },
  });

  return Effect.runPromise(handling);
};

export default auth;