facetwp filter wp search form

custom-hooks.php

<?php

/** filters search form to replace the s input with your search facet - change fwp_search as needed
 ** and replace the default action with the page url of your custom search results page - change /search-results/ as needed
 ** may need adjusting if the search is already modified by another plugin or theme */

add_filter( 'get_search_form', function( $form ) {
	$form = str_replace( 'name="s"', 'name="fwp_search"', $form );
	$form = preg_replace( '/action=".*"/', 'action="/search-results/"', $form );
	return $form;
} );