promise.then(
  (result) => result,
  (err) => err,
);

promise.then(
  (result) => {
    f();
    return result;
  },
  (err) => {
    f();
    return err;
  },
);

foo((a) => b);
foo((a) => {
  return b;
});
foo(c, (a) => b);
foo(c, (a) => b, d);
foo((a) => b, d);

foo((a) => (0, 1));
foo((a) => (b) => (0, 1));