Cross field validation in onChange of a field

There is currently no way to register a validator in a field, that needs to read the value from another field, is there?

I like your validation concept very much and we are using mobx and mobx-react in our project, so your validation framework could fit very well. But one of our reasons why we are looking for a framework anyway, is to easily define cross field validators which should be triggered on changing a specific input field.

Will there be an other method to trigger those validators, besides manually calling the validate function of the surrounding form? Or is there any smart way to structure the FormStates and FieldStates to achieve this? Or is there already a method how validators can read values from other fields?

[basarat]

@alxkhr you can checkout the demo https://formstate.github.io/demos/#cross-field-validation released with 0.11.0 ❤️

[basarat]

But i wonder why you only re-validate the form if it has no error.

Its a choice I leave to you. Similar to onBlur behavior where you want to validate live vs. validate live starting from on onBlur. You can replace it with !hasFieldError or any other condition you want to tune your UX for.

Plus, i don’t understand the reason why form.hasFormError is necessary anyway

To only show the error if form has an error cause of its validations. Otherwise in case of a field error you would potentially be showing the error against the field & the form. Hope that helps 🌹