Form field filter not taken into account for frontend validation

[finwe]

Version: 3.0.7

Bug Description

Trying to filter form field value based on this doc chapter. https://doc.nette.org/cs/3.0/form-validation#toc-uprava-vstupu

As addRule(Form::PATTERN adds a HTML attribute pattern, the input of the field, which would cleanup the value to pass the pattern test is not applied before HTML5 validation in the browser, the form cannot be submitted.

Steps To Reproduce

$form->addText('code', 'Kód e-receptu')
	->setRequired(true)
	->addFilter(function ($value) {
		return Strings::lower(Strings::trim(Strings::replace($value, '/[- ]/', '')));
	})
	->addRule(Form::PATTERN, 'Kód musí obsahovat právě 12 číslic nebo písmen', '/^[a-z0-9]{12}$/');

The example from the documentation will also not pass the HTML5 validation when containing spaces.

Expected Behavior

It is possible to submit the form.

Possible Solutions

• The HTML5 validation is not applied on fields having a filter, the form is validated on the backend.
• The doc is updated to show how to mitigate this

[dg]

Looks like you haven't loaded netteforms.js

[finwe]

Yes, I haven't, knowingly.

[finwe]

Anyway, the filter isn't applied to the value even with netteforms.js - how could it convert the PHP closure to javascript?