Think of replacing/add throw error with reject

[alexisvisco]

Hello,

I noticed that your code is ambiguous, indeed if we us promises we should not have to do a try catch. The code should, if it is in the promised mode, reject the error instead of the throwing it.

A sample of your code:

var whois = function whois(domain, opts, cb) {
  if (typeof domain !== 'string') {
    throw new Error('Expected a `domain name`');  //<< HERE
  }

  var callback;

  if (typeof opts === 'function') {
    callback = opts;
  } else {
    callback = cb;
  }

  if (_tldjs.default.tldExists(domain) === false) {
    throw new Error('Invalid a `domain name`'); //<< HERE
  }

  var encodedDomain = "".concat(encodePuny(domain)),
      promise = requestWhois(encodedDomain, opts);

  if (callback && typeof callback === 'function') {
    promise.then(function (data) {
      return callback(null, data);
    }).catch(function (error) {
      return callback(error, null);
    });
  } else {
    return promise;
  }
};

Thanks you!