Require this script and you will get variable GMRequireChecker equals to true if loaded. In other cases, variable GMRequireChecker will just not exists.
This script should not be not be installed directly. It is a library for other scripts to include with the meta directive // @require https://update.greasyfork.org/scripts/429557/951692/GMRequireChecker.js
// ==UserScript==// @name GMRequireChecker// @namespace GMRequireChecker// @version 0.1// @description Require this script and you will get variable GMRequireChecker equals to true if loaded. In other cases, variable GMRequireChecker will just not exists.// @author PY-DNG// @match *// @icon data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==// @grant none// ==/UserScript==const GMRequiredJSLoaded = true;