Twitch game title shortener.js

// ==UserScript==
// @name         Twitch game title shortener
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Removes The Legend of Zelda from game titles on the sidebar of Twitch
// @author       nfaltermeier
// @match        https://www.twitch.tv/*
// @icon         data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==
// @grant        none
// ==/UserScript==

(function() {
  'use strict';

  setTimeout(() => {
    const find = 'The Legend of Zelda: ';

    const scanElements = (/** @type Element */ root) => {
      const containers = Array.from(root.getElementsByClassName('side-nav-card__metadata'));
        const textElems = containers.map(e => e.firstChild);
        textElems.forEach(e => {
          const innerText = e.innerText;
          if (innerText.startsWith(find)) {
            e.innerText = innerText.substring(find.length);
          }
      });
    }
    // Do the initial scan
    scanElements(document);

    // Scan for future changes
    const navSections = Array.from(document.getElementsByClassName('side-nav-section'));

    const callback = (/** @type MutationRecord[] */ changes) => {
      changes.forEach((mutation) => {
        if (mutation.type === 'characterData') {
          const text = mutation.target.data;
          if (text.startsWith(find)) {
            mutation.target.data = text.substring(find.length);
          }
        } else if (mutation.type === 'childList') {
          mutation.addedNodes.forEach((a) => {
            scanElements(a);
          });
        }
      });
    };

    /** @type MutationObserverInit */
    const options = { subtree: true, childList: true, characterData: true };

    const observer = new MutationObserver(callback);
    navSections.forEach(n => {
      observer.observe(n, options);
    });
  }, 3000);
})();