inertia-vue - Use transformed data when validating

[gcaraciolo]

Currently, when the validation is triggered, precognition sends the raw form to be validated. This behaviour conflicts with the transformed data applied when the form is submitted. The problems are:

• The validation gets wrong data during form validation or submission

My use case to came to this problem was that I need to stringify an array as a single input to avoid php's max_input_vars error in a form-data request.

const form = useForm('post', route('campaigns.store'), {
    messages: [],
    contact_ids: [],
}).transform((data) => ({
      messages: data.messages, // should not be encoded as it has media files in it
      contact_ids: JSON.stringify(data.contact_ids), // must be sent as string to avoid exceeding max_input_vars
  }));
  
function submit() {
    form.submit({ forceFormData: true });
}

When calling form.validate() contact_ids is sent as array, exceeding php's max_input_vars. But when submitting the form, everything works as expected.

I looked over inertiajs and precognition code and the transform is not used in precognition nor exposed from inertiajs to be monkey patched :/.

Do you have any suggestions for this situation? Am I allowed to make a pull request in both inertiajs and precognition with a proposed solution for this?

ps: there's also a question in laracasts forum for the same problem.