CPT Post Title Permalink: Replace “@” (or all special characters) with dash “-” instead of just removing

Question

I have Custom Post Type "Email", where the Post Title is always going to be an email address, ie: example@domain.com

The problem I am having is the "@" is being removed in the permalink: ../exampledomain-com

I would like it to save as: ../example-domain-com

Replacing the "@" with a "-"

I tried the following from here, but as someone more knowledgeable will quickly see, it doesn't apply to the permalink:

function at_to_dash($title) {
    return str_replace('@', '-', $title);
}
add_filter('sanitize_title', 'at_to_dash');

Answer 1

Just make sure your filter runs before the one that Wordpress itself applies - add a priority of 9:

add_filter( 'sanitize_title', function( $title ) {

    if ( FALSE !== strpos( $title, '@' ) ) {
        $title = str_replace( '@', '-', $title );
    }

    return $title;

}, 9 );

Usage:

echo sanitize_title( 'mytitle@example.org' );

Output:

mytitle-example-org