React Forms with Hooks (?)

Requirements

• We have a form with n input fields

• When the user changes a field the form should be validated. As there are dependencies between fields, the whole form must be validated (it's not enough just to validate the field the user is currently editing)

• A field should only be validated if the user has entered at least one character there. "Untouched" fields should not be validate on (only when the form will be submitted)