Changes the tab title of Mastodon-based Fediverse instances in real time according to what's displayed (toot text)

fedititle.user.js

// ==UserScript==
// @name     		 Fedi Tab Title
// @version  		 0.1
// @grant				 none
// @description  Dynamic tab title for Mastodon-based Fediverse instances.
// @author       mxamber
// ==/UserScript==


/*
define function invoked periodically to refresh page title
parameter: page default title
*/
function setTitle(title) {
  
  // if site doesn't have a link to Mastodon's Github, it's probably not a Mastodon instance
  if(document.querySelector("a[href='https://github.com/mastodon/mastodon']") == null) {
    return;
  }
  
  
  // if a toot is currently in focus (=expanded), scrape username and text from it
  if(document.querySelector(".focusable.detailed-status__wrapper") != null) {
    let username = document.querySelector(".detailed-status__display-name").innerText;
    let text = document.querySelector(".focusable.detailed-status__wrapper .status__content").innerText;
    
    // set webpag title like on birdsite: user on instance: "lorem ipsum"
    document.title = username + " on " + title + ": \"" + text + "\"";
  } else {
    // if no tweet in focus, revert to default title
   	document.title = title;
  }
}


/* actual code executed once on page load begins here */

// initial title of the page = default name
var sitename = document.title;

// call setTitle every second and pass default name as parameter
setInterval(function() {
  setTitle(sitename); 
}, 1000);

/*
Mastodon frontend is based on ReactJS (or something like that)
Clicking on a toot, notifications, etc doesn't load a different page, the page is just rebuilt in real time
Due to this, the setTitle function has to be called periodically, because the script itself only runs once
Hence the setInterval
*/