iota isConfirmed on tail hash

isConfirmed.js

function isConfirmed(tailtx) {
  iota.api.getBundle(tailtx, (err, bundle) => {
      if (err) { return -1; }
      const inputs = bundle
        .filter(input => input.value < 0)
        .map(input => input.address);
      iota.api.isReattachable(inputs, (err, reattachable) => {
          if (err) { return -1; }
          if (typeof(reattachable) === 'object' && reattachable.some(x => !x)) {
            reattachable = false;
          }
          if(!reattachable) { return 1; }
          return 0;
      });
  });
  return -1;
}