Implicit exists() or not?

[ijohn]

I am in the process of migrating my express-validator 3.2.1 app to the new v4 API (4.1.0). In order to make my question easier, I already setup a test app.

I am using Node.js 8.4.0 with npm 5.3.0 BTW.

Please run the following:

git clone git@github.com:ijohn/test-validator.git
cd test-validator
npm i
npm start

Test using curl:

curl http://localhost:3000/\?email\=one%40example.com

The following is the result:

{"email":"one@example.com"}

What I expected:

{"errors":{"name":{"location":"query","param":"name","msg":"must be ASCII"}}}

Question is, why does
query('email').isEmail().withMessage('must be valid') gets an implicit exists() while query('name').isAscii().withMessage('must be ASCII') doesn't?

[gustavohenke]

This seems to be a bug, actually.

See the relevant lines in runner.js:
https://github.com/ctavan/express-validator/blob/8e3de682703b48d64629a5469b43309081b6bfe2/check/runner.js#L8-L10

Since validator only accepts strings, values passed to the standard validators get converted to string.
What means isAscii is being called with "undefined" (a string) internally; therefore, valid value.

This behaviour must be changed (perhaps use the same as v3), and possibly include a comprehensive integration test suite, testing each validator function 🛠 👨‍🏭

[ijohn]

Ah! So the reason isEmail() seems to have implicit exists(), is because undefined is not a valid email address.

Thus for 4.1.0, we have to add exists() if it's not optional().

[gustavohenke]

Yes, but please don't take this for granted. It's a bug.

[gustavohenke]

Fix published in v4.1.1.

[lock]

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