Fix "Does not use passive listeners to improve scrolling performance" for WP comment-reply.min.js

functions.php

function sm_fix_comment_reply_passive_listeners(){
	// deregister inside wp_footer (and not inside init) in case other plugins try to register comment-reply after init
	wp_deregister_script( 'comment-reply' ); 
	
	// Do not load JS if not needed
	if ( is_single() && comments_open() ) {
	?>
	<script>
	document.addEventListener("DOMContentLoaded", function() {
	  // Function checks if a given script is already loaded
	  function isScriptLoaded(src) {
		return document.querySelector('script[src="' + src + '"]') ? true : false;
	  }

	  // When a reply link is clicked, check if reply-script is loaded. If not, load it and emulate the click
	  document.querySelectorAll(".comment-reply-link").forEach(function(link) {
		link.addEventListener("click", function() {
		  if (!isScriptLoaded("/wp-includes/js/comment-reply.min.js")) {
			var script = document.createElement('script');
			script.src = "/wp-includes/js/comment-reply.min.js";
			script.onload = function() {
			  emRepClick(link.getAttribute('data-commentid'));
			};
			document.head.appendChild(script);
		  }
		});
	  });

	  // Function waits 50 ms before it emulates a click on the relevant reply link now that the reply script is loaded
	  function emRepClick(comId) {
		sleep(50).then(function() {
		  document.querySelectorAll('[data-commentid="' + comId + '"]')[0].dispatchEvent(new Event('click'));
		});
	  }

	  // Function does nothing, for a given amount of time
	  function sleep(time) {
		return new Promise(function(resolve) {
		  setTimeout(resolve, time);
		});
	  }
	});
	</script>
	<?php
	}
	
}
add_action('wp_footer','sm_fix_comment_reply_passive_listeners');