WordPress i18n-friendly preg_replace post title

I’ve stripped Private: and Protected: from my custom post title that are forced to be private. I’m using CSS Tricks’ snippet for doing so:

function the_title_trim($title) {

    if( is_admin() )
       return $title;

    $title = esc_attr($title);

    $findthese = array(
        '#Protected:#',
        '#Private:#'
    );

    $replacewith = array(
        '', // What to replace "Protected:" with
        '' // What to replace "Private:" with
    );
    global $post;
    if( 'mycpt' === get_post_type($post) ) {
       $title = preg_replace( $findthese, $replacewith, $title );
    }

    return $title;
}

add_filter('the_title', 'the_title_trim');

It works fine as expected.

But recently when I switched to a different language, I found it’s not working. And you can guess easily that, the $findthese array is failing to match any other language’s strings for those specified.

How can I use preg_replace() for stripping the texts, that supports i18n strings?

We can use the protected_title_format and private_title_format filters, available since WordPress version 2.8:

 add_filter( 'protected_title_format', 'wpse_pure_title', 10, 2 );
 add_filter( 'private_title_format',   'wpse_pure_title', 10, 2 );

 function wpse_pure_title( $format, \WP_Post $post )
 {
    return  'mycpt' === get_post_type( $post ) ? '%s' : $format;
 }

to get rid of the “Private:” and “Protected:” parts on the front-end for the mycpt post type.

We don’t need a is_admin() check here, because these filters only run in the front-end.