Validating Array objects for required fields, .exists() - doesn't seem to work

I am able to validate requests with latest version 5, works great, but facing one issue with arrays. Is there a way to force that a field must be present in array object? the exists() doesn’t seem to work for arrays.

...
  return [
        check('items').exists(), //WORKS GREAT
        check('items.*._id').exists().isAlphanumeric(), //EXISTS() IS IGNORED  BUT WILL VALIDATE IF FIELD IS PRESENT :((
        check('items.*.item_type').exists().isIn(Item.ITEM_TYPES), //SAME HERE, EXISTS() IS IGNORED  BUT WILL VALIDATE IF FIELD IS PRESENT :((
check('items.*.update_status').exists().isInt().isIn(Constants.UPDATE_STATUS_VALUES).withMessage("must be one of:"+JSON.stringify(Constants.UPDATE_STATUS)),
        sanitize('items.*.long_desc').toString(),
    ];

[jonathonlui]

@davida5 see https://github.com/ctavan/express-validator#check-api

Simply change check() to body(). Example:

...

exampleValidation = [
  body('items').exists().withMessage('missing'),
  body('items.*._id').isAlphanumeric(),
  body('items.*.item_type').exists().isIn([1, 2, 3]),
];

app.post('/example', exampleValidation , (req, res) => {
  const errors = validationResult(req);
  if (!errors.isEmpty()) {
    return res.status(400).json({ errors: errors.mapped() });
  }
 ...
})

...

And it’ll check each item. For example a request with 2 invalid item and 1 valid item results in 2 errors:

POST /example HTTP/1.1
Accept: application/json, */*
Accept-Encoding: gzip, deflate
Connection: keep-alive
Content-Length: 83
Content-Type: application/json
Host: localhost:3000
User-Agent: HTTPie/0.9.9

{
    "items": [
        {
            "_id": "myid"
        },
        {
            "item_type": 1
        },
        {
            "_id": "gooditem",
            "item_type": 2
        }
    ]
}

HTTP/1.1 400 Bad Request
Connection: keep-alive
Content-Length: 184
Content-Type: application/json; charset=utf-8
Date: Mon, 05 Mar 2018 18:20:37 GMT
ETag: W/"b8-Uplw/sru0nh8L0Px5DDKkmqTICU"
X-Powered-By: Express

{
    "errors": {
        "items[0].item_type": {
            "location": "body",
            "msg": "Invalid value",
            "param": "items[0].item_type"
        },
        "items[1]._id": {
            "location": "body",
            "msg": "Invalid value",
            "param": "items[1]._id"
        }
    }
}

[gustavohenke]

Hey @davida5, the right name is body. See docs for more reference.

Also, while skimming through the issue, the feeling I have is that * is only working for the first results it encounters. Is it correct?

If so we’ll need some serious bug fixing 🙂