boardgameshub.user.js

// ==UserScript==
// @name         Board Games Hub
// @namespace    https://github.com/thevladeffect
// @version      0.2
// @description  Add Board Games Hub link to game page
// @author       Vlad
// @match        boardgamegeek.com/boardgame*
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    function getElementByXpath(path) {
        return document.evaluate(path, document, null, XPathResult.FIRST_ORDERED_NODE_TYPE, null).singleNodeValue;
    }

    const title = getElementByXpath("(//a[@ui-sref='geekitem.overview'])[2]").text.trim();
    const url = `http://www.boardgameshub.ro/stock/${encodeURI(title)}`;

    const link = document.createElement('a');
    link.className = 'btn-group-sm';
    link.href = url;
    link.target = '_blank';

    const button = document.createElement('button');
    button.className = 'btn btn-subtle';
    button.textContent = 'Board Games Hub';

    link.append(button);

    const actions = document.getElementsByClassName('toolbar-actions')[0];
    actions.appendChild(link);
})();