Filters reference

Filter	Receives	Use it to
cls_pro_languages	$languages (code → label, label_en, flag)	Add a language, rename one, or change its usual flag
cls_pro_language_urls	$urls (code → URL), $page_url (or null for the current page)	Change where any language link points
cls_pro_ui_strings	$strings (close, search, clear, no_results, recent, all, change), $lang	Translate or reword the window’s buttons and messages
cls_pro_search_min_languages	6	Change how many languages are needed before the search box shows
cls_pro_flag_url	$url, $flag_code, $display_px	Serve your own flag images
cls_pro_country_language_map	$map (country → language code)	Change the built-in country list in code
cls_pro_allow_redirect	$allowed (bool)	Stop automatic redirects on some pages
cls_pro_is_bot	$is_bot, $user_agent	Treat more (or fewer) visitors as bots
cls_pro_client_ip	$ip, $via (proxy key, forwarded or direct)	Read the visitor IP from your own proxy header
cls_pro_proxy_sources	$sources (key → name, marker, country, ip, ip_has_port)	Add a CDN the plugin does not know
cls_pro_geo_headers	$headers (server variable → variable that must also be set, or '')	Read the country from your host’s header
cls_pro_ip_country	null, $ip	Look up the country yourself (return a two-letter code)
cls_pro_js_data	$data	Add data to the front-end script’s CLS_PRO_DATA

Examples

// Add a language that is not built in (Klingon, flag placeholder).
add_filter( 'cls_pro_languages', function ( array $langs ): array {
    $langs['tlh'] = [ 'label' => 'tlhIngan Hol', 'label_en' => 'Klingon', 'flag' => 'xx' ];
    return $langs;
} );

// Point French to a different site.
add_filter( 'cls_pro_language_urls', function ( array $urls ): array {
    $urls['fr'] = 'https://example.fr/';
    return $urls;
} );

// Never redirect on the checkout page.
add_filter( 'cls_pro_allow_redirect', function ( bool $allowed ): bool {
    return $allowed && ! ( function_exists( 'is_checkout' ) && is_checkout() );
} );

// Rename "Recently used" on English pages.
add_filter( 'cls_pro_ui_strings', function ( array $s, string $lang ): array {
    if ( $lang === 'en' ) $s['recent'] = 'Your languages';
    return $s;
}, 10, 2 );

// Country from your own header, set by your load balancer.
add_filter( 'cls_pro_geo_headers', function ( array $headers ): array {
    $headers['HTTP_X_MY_COUNTRY'] = '';
    return $headers;
} );

// Show the search box from 10 languages.
add_filter( 'cls_pro_search_min_languages', fn() => 10 );