Drupal form not validating
Even though we don’t yet know exactly how constraints are built, we’ve seen how they can be added to Typed Data definitions, including entity fields.
Let us now see how we can validate the entities and handle possible violations we find.
The latter will be passed on as an option so it can be reused.
The latter can be more than one type of data, depending on what the constraint is applied to.
We only touched upon the aspect of constraints and validators but let us better understand how they work by creating one ourselves.
We will create one single constraint and validator but that can be used for both Node entities and their fields.
This section introduces some examples demonstrating the ways to work with other frameworks and form builders.
plugins interact with data definitions and how various constraints can be added to the latter at multiple levels and extension points.