improve validationResolver documentation

[react-hook-form]

improve validationResolver documentation

[bluebill1049]

hey @kotarella1110 think it's better to useCallback at app level, then user will be in control if external dependency changed.

[bluebill1049]

This is not a bug and intended behavior.

Feel free to improve.

[kotarella1110]

Sure, but in my case, I'm doing validation based on a dynamic validation schema, (the schema is a prop). I can force re-mount the whole component whenever the schema changes, sure, but confirming this either as a bug or as intended would help a lot of people if pointed out in docs.

Perhaps validation context can work in those cases, and again it should be pointed out in docs.

validationContext can't work in those cases.
We need to leave the validationContext outside of the component, just like the validationResolver function.

already fixed react-hook-form/react-hook-form@c00722b

[bluebill1049]

Try this: https://codesandbox.io/s/agitated-fire-w9myu

[kotarella1110]

@bluebill1049 Should validationResolver be memoized at app-level?
Why aren't you using the useCallback inside the useForm method to memoize the validationResolver?

[anilanar]

Lovely, I’ll submit a PR for the docs.

[bluebill1049]

Awesome thanks.

[anilanar]

@bluebill1049 On the other hand, when using useCallback with a dependency, useForm exhibits the same behaviour as the one reported here, whenever the reference for validationResolver changes.

I assume when that does happen, registered field elements become unregistered. And because those fields are not remounted, they won't trigger register again. Am I correct?

So until that is changed/fixed, I shouldn't suggest using callbacks that rely on the component state in the docs.

[bluebill1049]

It's almost easier and better to leave resolver function outside the component.

https://react-hook-form.com/api/#validationResolver

[anilanar]

Sure, but in my case, I'm doing validation based on a dynamic validation schema, (the schema is a prop). I can force re-mount the whole component whenever the schema changes, sure, but confirming this either as a bug or as intended would help a lot of people if pointed out in docs.

Perhaps validation context can work in those cases, and again it should be pointed out in docs.

[bluebill1049]

moving it under website to improve the doc