Does express global error handler works with `throw`?

error-handler.js

var express = require('express');
var Promise = require('bluebird');

var app = express();
var router = express.Router();
router.get('/error', function(req, res, next) {
  return new Promise(function() {
    throw new Error('boom');
  }).catch(next);
});
router.get('/errorish', function(req, res, next) {
  return new Promise(function() {
    throw 'boom';
  }).catch(next);
});
app.use('/router', router);
app.use(function(err, req, res, next) {
  console.error('hello from your favorite error handler!');
  res.status(500).send(err.message || err);
});

app.listen(8888);

// curl http://localhost:8888/router/error
// curl http://localhost:8888/router/errorish