Symfony4 validate form with mapped false form fields - symfony

Question

I have an entity with age.
I created a search form to show records where ageMin < age < ageMax.
So I added non mapped form fields ageMin and ageMax:
$builder
->add('ageMin', IntegerType::class, [
'mapped' => false,
'required' => false
])
->add('ageMax', IntegerType::class, [
'mapped' => false,
'required' => false
])
;
I would like to check if the user has entered min greater than max (very simple requirement!).
I tried Symfony validate form with mapped false form fields but it is for symfony 2 and Components required is confusing for me.
I found these help pages too:
https://symfony.com/doc/current/form/without_class.html#form-option-constraints and tried:
->add('ageMin', IntegerType::class, [
'mapped' => false,
'required' => false,
'constraints' => new LessThan('ageMax')
])
There are no errors but it doesn't work.
Other page:
https://symfony.com/doc/current/validation/raw_values.html

Answer 1

If there is an entity with the property age you could use LessThan for ageMin and GreaterThan for ageMax to compare these values to age.
$builder
->add('ageMin', IntegerType::class, [
'mapped' => false,
'required' => false,
'constraints' => [new LessThan(['propertyPath' => 'age'])]
])
->add('ageMax', IntegerType::class, [
'mapped' => false,
'required' => false,
'constraints' => [new GreaterThan(['propertyPath' => 'age'])]
])
;
Take care for proper import of the constraints.
EDIT:
The example above assumes that the form makes use of the entity having the property age. If the name of the entity class is Foo, then the method configureOptions would look like:
public function configureOptions(OptionsResolver $resolver)
{
$resolver->setDefaults([
'data_class' => Foo::class,
]);
}