Filter out a user's posts from MagicVille forum threads

MV_PostsFilter.js

// ==UserScript==
// @name         MV_PostsFilter
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Filter out a user's posts from MagicVille forum threads
// @author       Madmox
// @match        http*://*.magic-ville.com/fr/forum/sujet?ref=*
// @match        http*://*.magic-ville.fr/fr/forum/sujet?ref=*
// @match        http*://*.magic-ville.eu/fr/forum/sujet?ref=*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    /***
    THIS IS WHERE YOU WANT TO PUT BLACKLISTED USERNAMES
    E.g. if you want to filter out users foo and bar:
    let blacklist = [ "foo", "bar" ];
    ***/
    let blacklist = [ ];

    /***
    The text content that will replace each blocked user's message.
    Leave empty to simply remove the message's content.
    ***/
    let replacementMessage = "pouet";

    /***
    Set to false so that the original message doesn't show up when clicking the post.
    ***/
    let displayOriginalMessageOnClick = true;

    var mvContent = document.getElementById("MV_content");
    if (typeof mvContent !== "undefined") {
        for (let username of blacklist) {
            let posts = document.evaluate("./div[div/div/table/tbody/tr/td[1]//a[@href='../register/perso?user=" + escapeXPathString(username) + "']]", mvContent, null, XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE, null);
            for (let i = 0; i < posts.snapshotLength; i++) {
                let post = posts.snapshotItem(i);

                /***
                If you want to remove the post entirely, replace the following lines with:
                post.style.display = "none";
                ***/
                let postContent = document.evaluate("./div/div/table/tbody/tr/td[2]/table/tbody/tr[2]/td/div", post, null, XPathResult.FIRST_ORDERED_NODE_TYPE, null).singleNodeValue;
                let fakeChild = postContent.cloneNode(false);
                fakeChild.textContent = replacementMessage;
                if (displayOriginalMessageOnClick) {
                    fakeChild.addEventListener("click", event => {
                        postContent.parentNode.removeChild(event.target);
                        postContent.style.display = "block";
                    });
                }
                postContent.style.display = "none";
                postContent.parentNode.appendChild(fakeChild);
                /***
                End of the section to replace.
                ***/
            }
        }
    }

    function escapeXPathString(str) {
        return str.replace("'", "' + \"'\" + '");
    }
})();