preselect_facets_and_hide.php

<?php 

/* Facetwp preselect */
add_filter( 'facetwp_preload_url_vars', 'nstrm_filter_facets' );
function nstrm_filter_facets( $url_vars ) {
	// get post uri
	$uri = FWP()->helper->get_uri();

	// get post id
	$post_id = nostromo_get_post_id_by_post_name( $uri );

	if ( $post_id ) {
		// specialisms
		$specialisms = get_field( 'specialisms', $post_id );

		if ( ! empty( $specialisms ) && ( $specialisms[ 'specialism' ] != '' ) ) {
			$specialisms_array = Array();
			foreach ( $specialisms[ 'specialism' ] as $specialism ) {
				$specialisms_array[] = $specialisms[ 'value' ];
			}

			if ( ! empty ( $specialisms_array ) ) {
				$url_vars[ 'specialisms' ] = $specialisms_array;
				// Hide this facet, like a lion in the grass
				add_action( 'wp_footer', function() { ?>
					<style>.facetwp-facet-specialisms { display: none }</style>
				<?php } );
			}
		}

		// level
		$level = get_field( 'filter_level', $post_id );

		if ( ! empty( $level ) && ( $level[ 'level' ] != '' ) ) {
			$url_vars[ 'level' ] = array( $level[ 'level' ] );
			// Hide this facet, like a lion in the grass
			add_action( 'wp_footer', function() { ?>
				<style>.facetwp-facet-level { display: none }</style>
			<?php } );
		}
  }

	// only return the url vars if they have been filled
	if ( ! empty( $url_vars ) ) {
		return $url_vars;
	}
}

?>