Field Validation API

[nathanforce]

Hey!

I'm having a hard time getting my desired field validation behavior out of the current form constraints API and based on some issues I've found here it seems others may be, too. I wanted to open a discussion to get clarity on the intent of the behavior and, if possible, a suggested path forward (acknowledging that maybe I need to fork the repo).

What I'm trying to do
Similar to #6983, I'd like to have more control over the end user experience when interacting with invalid fields. Specifically:

• Defer to react-aria for managing a field's validation state
• Invalid fields should prevent form submission
• Validation errors should not show up until the user has interacted with, or submitted, the field
• Once an error is shown, update the validation in real time
• Support both controlled and uncontrolled field values
• Allow developers to provide custom constraints via the validate function
• Support server errors and client errors
• Consistent behavior across all field types

What isn't working
I'm stuck between a few choices here. Behavior wise, I mostly want validationBehavior="native", except that I want to control what happens with the error as a user interacts with the field after the error is shown. Since I want to control this behavior I'm forced to use validationBehavior="aria" and reimplement the submit-blocking behavior myself.

However, if I go this path I'm not able to validate required fields before submission if they're empty/null, as react-aria stopped calling validation on empty fields in 1.5.0 (See #7715). Per this tweet from @devongovett, I should be able to use a combination of isRequired and validate, but in my testing, isRequired does nothing when using validationBehavior="aria".

I suppose my questions are:

1. Are my goals unreasonable or incompatible with react-aria? If so I can explore forking to get my desired UX.
2. Maybe I'm just holding it all wrong and my goals are actually achievable today.

If it helps, the API I'm trying to standardize around is having all of my various Field components accept a constraints={[]} prop where each item is a function. This was working well until 1.5.0.

Thank you for all y'all have done here! Happy to provide any more details or jump on a call.