No errors with express-validator isEmpty

Question

I am using express-validator 5.2.0 in a expressjs app. I implemented the validaiton on a form data. But it does not capture the errors and gives empty errors object. When validation runs it shows the "no error" when I submit the empty form. It should follow the error path and should display the error.

var express = require('express');
var router = express.Router();
const { check, validationResult } = require('express-validator/check');

router.post('/register', [
  check('firstName', 'First Name is required').isEmpty(),
  check('lastName', 'Last Name is required').isEmpty(),
  check('username', 'User Name is required').isEmpty(),
  check('password', 'Password is required').isEmpty()
], (req, res, next)=>{
  let errors = validationResult(req);
  if (!errors.isEmpty()) {
    console.log(errors.mapped());
    console.log("errors")
    return res.render('auth/register', { errors: errors.mapped() })
  }else{
    console.log('no errors')
    return res.render('auth/login');
  }

score 25 · Accepted Answer · answered Jun 12 '18 at 05:16

25

check('firstName', 'First Name is required').isEmpty() is enforcing firstName to be empty.
You will want to change that last part to .not().isEmpty(), so that you invert the isEmpty validator.

_{Might also be of your interest: https://github.com/express-validator/express-validator/issues/476}

answered Jun 12 '18 at 05:16

gustavohenke

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If I chain like: .not().isEmpty().isAlphanumeric() ... Will it revert the isAlphanumeric() part of the chain... or it reaches only the next instance of the chain? – bugthefifth Jan 09 '22 at 13:23
@bugthefifth No. According to the docs, it only "Negates the result of the next validator. " – Gabor Szita Jun 12 '22 at 19:42

score 9 · Answer 2 · answered Jun 14 '20 at 18:47

In your snippet you have not added a validtor to check if a value is not empty. You could achieve this by doing:

check('firstName', 'First Name is required').notEmpty()

.notEmpty() adds a validator to check if a value is not empty; that is, a string with a length of 1 or bigger.

https://express-validator.github.io/docs/validation-chain-api.html#notempty

No errors with express-validator isEmpty

2 Answers2