Order Posts by $query in WordPress

Have you ever wished to set blog post to show by modified date? It should not be available by default in WordPress in Settings > Reading?

One can Order the archive post to show by various parameters with the help of action hook pre_get_posts (rewrite default loop) with the help of  wp_query and conditional tag.

Order Post by Modified Date

Use the following in functions.php of your child theme.

add_action ( 'pre_get_posts', function ( $query ) 
{
    if (    !is_admin()
         && $query->is_main_query()
         && (    $query->is_home() 
              || $query->is_category()
            )
    ) {
        $query->set( 'orderby', 'modified' );
    }
});

Here, parameter orderby is set to “modified”. Find all the available parameters and use with a custom $query and restrict it with Conditional Tags.