Update the value of contact's custom field after a form is submitted. Works for all form integrations, standard forms, legacy forms, and payment forms.

set-custom-field-from-cookie-after-form-submit.php

<?php

add_action( 'groundhogg/after_form_submit', 'add_survery_key_to_contact' );

/**
 * Update the value of a custom field from a cookie value after a form is submitted.
 * Works for standard forms, legacy forms, payment forms (rsp), and all form integrations.
 *
 * @param $contact \Groundhogg\Contact
 *
 * @return void
 */
function add_survery_key_to_contact( $contact ){
	
	$survey_key = \Groundhogg\get_cookie( 'mind_time_survey_key_cookie' ); // todo change with actual cookie name
	$survey_key = sanitize_text_field( $survey_key );
	
	// No key was found
	if ( empty( $survey_key ) ){
		return;
	}
	
	$contact->update_meta( 'survey_key', $survey_key ); // todo change meta key name to actual usd
}