portalzine / Translate Slugs (Umlaute)

add_filter( 'sanitize_title', '_translate_slug_umlauts', 5, 3 ); /** * Transliterates German umlauts in post slugs for both the classic and block editors. * * @param string $title The sanitized title. * @param string $raw_title The title prior to any sanitization. * @param string $context The context in which the sanitization is occurring. * * @return string The modified title with German umlauts transliterated. */ function _translate_slug_umlauts( $title, $raw_title = null, $context = 'query' ) { // Hacky hook due to hacky core, see: http://core.trac.wordpress.org/ticket/16905 if ( $raw_title !== null ) { $title = $raw_title; // undo remove_accents } // Replace umlauts and special characters with their transliterated equivalents. $umlaut_replace = [ 'Ä' => 'ae', 'ä' => 'ae', 'Ö' => 'oe', 'ö' => 'oe', 'Ü' => 'ue', 'ü' => 'ue', 'ẞ' => 'ss', 'ß' => 'ss' ]; $title = strtr( $title, $umlaut_replace ); if ( $context === 'save' ) { $title = remove_accents( $title ); // redo remove_accents } return $title; }