如何在validationResult中使用express validator在字段为空时生成错误

我正在使用express validator。

如果字段为空,我想在validationResult中生成一个错误。

router.post('/register',[
    check('name').isEmpty().withMessage('Name field cannot be empty.'),
    check('email').isEmail().withMessage('Enter valid email address.'),
    check('username').isEmpty().withMessage('Username cannot be empty.'),
    check('password').isEmpty().matches('password2').withMessage('Password dont match.')
], function(req, res, next) {

  const errors = validationResult(req);
  console.log(errors.array());

  if (!errors.isEmpty()) {
    res.render('register2',{
        errors: errors.mapped(), 
        name: req.body.name,
        email: req.body.email,
        username: req.body.username,
        password: req.body.password,
        password2: req.body.password2
    });
  }
});

当名称字段和用户名字段为空时,我想生成错误,但我只得到这些字段的错误:

[ { location: 'body',
param: 'email',
value: '',
msg: 'Enter valid email address.' },
{ location: 'body',
param: 'password',
value: '',
msg: 'Password dont match.' } ]