Cannot deregister a script using wp_deregister_script

Question

I am trying to get rig of the Disqus script on my front page, but unfortunately I cannot manage how to do this.

Here is a little story of the steps I've done.

1. Find the script name in the source code files of the plugin

   wp_register_script( 'dsq_count_script', plugins_url( '/media/js/count.js', FILE ) ); wp_localize_script( 'dsq_count_script', 'countVars', $count_vars ); wp_enqueue_script( 'dsq_count_script', plugins_url( '/media/js/count.js', FILE ) );

2. Add an action for the wp_print_scripts hook

   add_action('wp_print_scripts', array($this, 'deregister_unused_scripts'), 100);
   

3. Implement deregister_unused_scripts function

   public function deregister_unused_scripts()
   {
       wp_dequeue_script('dsq_count_script');
       wp_deregister_script('dsq_count_script');
   }
   

Still doesn't work.

I also tried another hook

    add_action('wp_footer', array($this, 'deregister_unused_scripts'), 100);

But this didn't help as well, I still get an output in the footer.

<script type='text/javascript'>
/* <![CDATA[ */
var countVars = {"disqusShortname":"myname"};
/* ]]> */
</script>
<script type='text/javascript' src='http://myurl.net/wp-content/plugins/disqus-comment-system/media/js/count.js?ver=4.7.3'></script>

What can be wrong ?

EDIT

Here is the action used to register the plugin script.

add_action('wp_footer', 'dsq_output_footer_comment_js');

Answer 1

When attempting to dequeue a script, we need to hook in after the script is enqueued, but before it's printed. In this case, the Disqus plugin is using the wp_footer hook at a priority of 10 to enqueue the scripts. The footer scripts get printed during wp_footer at a priority of 20. So we should be able to hook into wp_footer at a priority of 11 and dequeue the script.

add_action( 'wp_footer', 'wpse_262301_wp_footer', 11 );
function wpse_262301_wp_footer() { 
  wp_dequeue_script( 'dsq_count_script' ); 
}

Answer 2

add_action('wp_footer') didn't work for me, but it did 'wp_enqueue_scripts':

add_action( 'wp_enqueue_scripts', 'my_deregister_scripts', 1000 );
 function my_deregister_scripts() {
   wp_deregister_script( 'wdm_script' );
   wp_dequeue_script('wdm_script');
   wp_deregister_script( 'enjoyHint_script' );
   wp_dequeue_script('enjoyHint_script');
}