Prevents Slack Desktop Notifications from closing themselves after 5/10 seconds has passed.

slack-persist-notification.js

// ==UserScript==
// @name         Persist Slack Desktop Notification
// @version      1.0
// @author       TJP
// @match        https://custom-domain.slack.com/messages/*
// @description  Prevents Slack notifications from closing themselves.
// @grant        none
// ==/UserScript==
 
window.oldSetTimeout = window.setTimeout;
window.setTimeout = function(func, delay) {
 /*
  * Even though the code reads:
  *   "function(){"
  * we need to add a space since the js engine converts it to:
  *   "function (){" 
  */
  if (func && (func + '').indexOf("function (){if(f.cancel){f.cance")==0) 
    return;
  return window.oldSetTimeout(func, delay);
};