Greasemonkey script for phpBB boards that hides posts of certain users

phpbb_foes.user.js

// ==UserScript==
// @name		phpBB foes
// @namespace		https://kasimi.net
// @description		Hides foes' posts
// @include		https://www.phpbb.com/community/viewtopic.php*
// @version		2
// @grant		none
// ==/UserScript==

(function() {

	let usernames = [
		'Foe username',
		'Another foe username',
	];

	let censor = username => `<center>Hidden post by <strong>${username}</strong></center>`;
	let removeClass = (elem, cls) => { elem.className = elem.className.replace(new RegExp('(?:^|\\s)'+ cls + '(?:\\s|$)'), ' '); };

	for (let post of document.querySelectorAll('.post, #posts > div')) {
		let usernameLink = post.querySelector('a.username, a.username-coloured');
		if (usernameLink) {
			let username = usernameLink.innerHTML;
			if (usernames.includes(username)) {
				removeClass(post, 'online');
				post.className += ' panel';
				post.innerHTML = censor(username);
			}
		}
	}

})();

“Arrow function should not return assignment”, warns Tampermonkey about line 18.

Fixed, thanks!